Date: Fri, 26 Feb 16 01:20:49 GMT Subject: physics daily 49 new + 17 crosses received by eprepget ------------------------------------------------------------------------------ ------------------------------------------------------------------------------ Send any comments regarding submissions directly to submitter. ------------------------------------------------------------------------------ Archives at http://arxiv.org/ To unsubscribe, e-mail To: physics@arXiv.org, Subject: cancel ------------------------------------------------------------------------------ received by eprepget from Wed 24 Feb 16 21:00:00 GMT to Thu 25 Feb 16 21:00:00 GMT ------------------------------------------------------------------------------ \\ arXiv:1602.07680 Date: Tue, 23 Feb 2016 22:29:09 GMT (259kb) Title: Using Categorization of Problems as an Instructional Tool to Help Introductory Students Learn Physics Authors: Andrew Mason and Chandralekha Singh Categories: physics.ed-ph Comments: 6 pages, 1 figure. arXiv admin note: substantial text overlap with arXiv:1602.07677 Journal-ref: Physics Education (IOP), 51(2), 025009, 2016 DOI: 10.1088/0031-9120/51/2/025009 \\ The ability to categorize problems based upon underlying principles, rather than contexts, is considered a hallmark of expertise in physics problem solving. With inspiration from a classic study by Chi, Feltovich, and Glaser, we compared the categorization of 25 introductory mechanics problems based upon similarity of solution by students in large calculus-based introductory courses with physics faculty and Ph.D. students. Here, we summarize the study and suggest that a categorization task, especially when conducted with students working with peers in small groups, can be an effective pedagogical tool to help students in introductory physics courses learn to discern the underlying similarity between problems with diverse contexts but the same underlying physics principles. \\ ( http://arxiv.org/abs/1602.07680 , 259kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07681 Date: Wed, 24 Feb 2016 01:53:10 GMT (2754kb) Title: Tetrahedral Units: For Dodecahedral Super-Structures Authors: Y. Ortiz, D. J. Klein and J. F. Liebman Categories: physics.chem-ph \\ Different novel organic-chemical possibilities for tetrahedral building units are considered, with attention to their utility in constructing different super-structures. As a representative construction we consider the use of sets of 20 such identical tetrahedral units to form a super-dodecahedron. \\ ( http://arxiv.org/abs/1602.07681 , 2754kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07686 Date: Wed, 24 Feb 2016 17:52:01 GMT (50kb,D) Title: Effect of Misconception on Transfer in Problem Solving Authors: Chandralekha Singh Categories: physics.ed-ph Comments: 4 pages, PACS: 01.40Fk,01.40.gb,01.40G-,1.30.Rr, Keywords: physics education research, transfer of learning, analogy, isomorphic problems, pedagogy, teaching. arXiv admin note: substantial text overlap with arXiv:1602.07678 Journal-ref: Proceedings of the Physics Education Research Conference, Syracuse, NY, AIP, AIP Conference Proceedings, Melville New York 951, 196-199, (2007) DOI: 10.1063/1.2820931 \\ We examine the effect of misconceptions about friction on students' ability to solve problems and transfer from one context to another. We analyze written responses to paired isomorphic problems given to introductory physics students and discussions with a subset of students. Misconceptions associated with friction in problems were sometimes so robust that pairing them with isomorphic problems not involving friction did not help students fully discern their underlying similarities. \\ ( http://arxiv.org/abs/1602.07686 , 50kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07717 Date: Wed, 24 Feb 2016 21:26:39 GMT (2435kb) Title: A physical zero-knowledge object comparison system for nuclear warhead verification Authors: S\'ebastien Philippe, Robert J. Goldston, Alexander Glaser, Francesco d'Errico Categories: physics.ins-det nucl-ex physics.soc-ph Comments: 15 pages and 4 figures including methods \\ Zero-knowledge proofs are mathematical cryptographic methods to demonstrate the validity of a claim while providing no further information beyond the claim itself. The possibility of using such proofs to process classified and other sensitive physical data has attracted attention especially in the field of nuclear arms control. Here we demonstrate a non-electronic fast neutron differential radiography technique using superheated emulsion detectors that can confirm that two objects are identical without revealing their geometry or composition. In addition to the use of such a technique as part of a verification system that could confirm the authenticity of nuclear weapons without sharing any secret design information, we provide definitive evidence that measuring sensitive data is not required to perform comparisons of physical properties. \\ ( http://arxiv.org/abs/1602.07717 , 2435kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07718 Date: Wed, 24 Feb 2016 21:33:35 GMT (2065kb,D) Title: Vertically bounded double diffusive convection in the fingering regime: comparing no-slip vs free-slip boundary conditions Authors: Yantao Yang and Roberto Verzicco and Detlef Lohse Categories: physics.flu-dyn physics.ao-ph Comments: 11 pages, 4 figures \\ Vertically bounded fingering double diffusive convection (DDC) is numerically investigated, focusing on the influences of different velocity boundary conditions, i.e. the no-slip condition which is inevitable in the lab-scale experimental research, and the free-slip condition which is an approximation for the interfaces in many natural environments, such as the oceans. For both boundary conditions the flow is dominated by fingers and the global responses follow the same scaling laws, with enhanced prefactors for the free-slip cases. Therefore, the laboratory experiments with the no-slip boundaries serve as a good model for the finger layers in the ocean. Moreover, in the free-slip case although the tangential shear stress is eliminated at the boundaries, the local dissipation rate in the near-wall region may exceed the value found in the no-slip cases, which is caused by the stronger vertical motions of fingers and sheet structures near the free-slip boundaries. This counter intuitive result might be relevant for properly estimating and modelling the mixing and entrainment phenomena at free-surfaces and interfaces. \\ ( http://arxiv.org/abs/1602.07718 , 2065kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07725 Date: Wed, 24 Feb 2016 21:58:42 GMT (44kb,D) Title: Student understanding of Symmetry and Gauss' law Authors: Chandralekha Singh Categories: physics.ed-ph Comments: 4 pages, PACS: 01.40Fk,01.40.gb,01.40G-,1.30.Rr, Keywords: Physics Education Research, Gauss's law, teaching, learning, pedagogy, assessment. arXiv admin note: substantial text overlap with arXiv:1602.07376 Journal-ref: Proceedings of the Physics Education Research Conference, Sacramento, CA, AIP Conference Proceedings, Melville New York 790, 65-68, (2005) DOI: 10.1063/1.2084702 \\ Helping students learn why Gauss' law can or cannot be easily applied to determine the strength of the electric field at various points for a particular charge distribution, and then helping them learn to determine the shape of the Gaussian surfaces if sufficient symmetry exists can develop their reasoning and problem solving skills. We investigate the difficulties that students in calculus-based introductory physics courses have with the concepts of symmetry, electric field and electric flux that are pivotal to Gauss' law of electricity. Determination of the electric field using Gauss' law requires discerning the symmetry of a particular charge distribution and being able to predict the direction of the electric field everywhere if a high symmetry exists. It requires a good grasp of how to add the electric field vectors using the principle of superposition, and the concepts of area vector and electric flux. We administered free response and multiple-choice questions and conducted interviews with individual students using a think-aloud protocol to elucidate the difficulties students have with the concepts of symmetry, electric field and electric flux. Here, we discuss student responses to some questions on a multiple-choice test administered to them. The test can be used as a teaching and assessment tool. \\ ( http://arxiv.org/abs/1602.07725 , 44kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07728 Date: Wed, 24 Feb 2016 22:13:42 GMT (6085kb,D) Title: Density matrix reconstruction of three-level atoms via Rydberg electromagnetically induced transparency Authors: V. Gavryusev, A. Signoles, M. Ferreira-Cao, G. Z\"urn, C. S. Hofmann, G. G\"unter, H. Schempp, M. Robert-de-Saint-Vincent, S. Whitlock and M. Weidem\"uller Categories: physics.atom-ph cond-mat.quant-gas quant-ph Comments: 12 pages, 5 figures \\ We present combined measurements of the spatially-resolved optical spectrum and the total excited-atom number in an ultracold gas of three-level atoms under electromagnetically induced transparency conditions involving high-lying Rydberg states. The observed optical transmission of a weak probe laser at the center of the coupling region exhibits a double peaked spectrum as a function of detuning, whilst the Rydberg atom number shows a comparatively narrow single resonance. By imaging the transmitted light onto a charge-coupled-device camera, we record hundreds of spectra in parallel, which are used to map out the spatial profile of Rabi frequencies of the coupling laser. Using all the information available we can reconstruct the full one-body density matrix of the three-level system, which provides the optical susceptibility and the Rydberg density as a function of spatial position. These results help elucidate the connection between three-level interference phenomena, including the interplay of matter and light degrees of freedom and will facilitate new studies of many-body effects in optically driven Rydberg gases. \\ ( http://arxiv.org/abs/1602.07728 , 6085kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07740 Date: Wed, 24 Feb 2016 22:54:50 GMT (679kb,D) Title: Teaching practices of graduate teaching assistants Authors: Eric Hickok Categories: physics.ed-ph Comments: Master's Project at San Jose State University, advised by Cassandra Paul. December 2015 \\ Physics education research has consistently shown that students have higher learning outcomes when enrolled in interactive-engagement courses. Consequently, many schools are actively reforming their introductory curricula. For courses where the interactive sections (labs, tutorials, and/or workshops) are mostly taught by graduate student teaching assistants (TAs), good TAs are instrumental to the success of the reform. Many studies have investigated specific interactions between TAs and students, but more can be learned through a holistic examination of TA-student interactions. Over the course of one semester, I observed TAs in their various teaching roles using the Real-time Instructor Observation Tool (RIOT). These observations serve to show what TAs may "default to" with little to no intervention. I present a snapshot of a department in the early stages of reform and discuss the implications of my findings as they relate to the professional development of our TAs. \\ ( http://arxiv.org/abs/1602.07740 , 679kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07746 Date: Wed, 24 Feb 2016 23:02:53 GMT (76kb) Title: Interactive video tutorials for enhancing problem solving, reasoning, and meta-cognitive skills of introductory physics students Authors: Chandralekha Singh Categories: physics.ed-ph Comments: 4 pages; PACS: 01.40Fk,01.40.gb,01.40G-,1.30Rr; Keywords: Physics Education Research, online tutorial, web-based tutorial, interactive, adaptive, teaching, learning, pedagogy Journal-ref: Proceedings of the Physics Education Research Conference, Madison, WI, AIP Conference Proceedings, Melville New York 720, 177-180, (2004) DOI: 10.1063/1.1807283 \\ We discuss the development of interactive video tutorial-based problems to help introductory physics students learn effective problem solving heuristics. The video tutorials present problem solving strategies using concrete examples in an interactive environment. They force students to follow a systematic approach to problem solving and students are required to solve sub-problems (research-guided multiple choice questions) to show their level of understanding at every stage of prob lem solving. The tutorials are designed to provide scaffolding support at every stage of problem solving as needed and help students view the problem solving process as an opportunity for knowledge and skill acquisition rather than a "plug and chug" chore. A focus on helping students learn first to analyse a problem qualitatively, and then to plan a solution in terms of the relevant physics principles, can be useful for developing their reasoning skills. The reflection stage of problem solving can help students develop meta-cognitive skills because they must focus on what they have learned by solving the problem and how it helps them extend and organize their knowledge. Preliminary evaluations show that a majority of students who are unable to solve the tutorial problems without help can solve similar problems after working through the video tutorial. Further evaluation to assess the development of useful skills in tutorial learners vs. control group is underway. \\ ( http://arxiv.org/abs/1602.07746 , 76kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07753 Date: Wed, 24 Feb 2016 23:50:15 GMT (81kb) Title: Short-range photoassociation from the inner wall of the lowest triplet potential of $^{85}$Rb$_2$ Authors: R. A. Carollo, J. L. Carini, E. E. Eyler, P. L. Gould, and W. C. Stwalley Categories: physics.atom-ph Comments: 6 pages, 3 figures \\ Ultracold photoassociation is typically performed at large internuclear separations, where the scattering wavefunction amplitude is large and Franck-Condon overlap is maximized. Recently, work by this group and others on alkali-metal diatomics has shown that photoassociation can efficiently form molecules at short internuclear distance in both homonuclear and heteronuclear dimers. We propose that this short-range photoassociation is due to excitation near the wavefunction amplitude maximum at the inner wall of the lowest triplet potential. We show that Franck-Condon factors from the highest-energy bound state can almost precisely reproduce Franck-Condon factors from a low-energy scattering state, and that both calculations match experimental data from the near-zero positive-energy scattering state with reasonable accuracy. We also show that the corresponding photoassociation from the inner wall of the ground-state singlet potential at much shorter internuclear distance is weaker and undetectable under our experimental conditions, as predicted from Franck-Condon factors. \\ ( http://arxiv.org/abs/1602.07753 , 81kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07756 Date: Thu, 25 Feb 2016 00:08:26 GMT (6kb) Title: Students' conceptual knowledge of energy and momentum Authors: Chandralekha Singh Categories: physics.ed-ph Comments: 4 pages, PACS: 01.40Fk,01.40.gb,01.40G-,1.30.Rr; Keywords: physics education research, pedagogy, teaching, learning, assessment, energy, momentum, student difficulties. arXiv admin note: substantial text overlap with arXiv:1602.06497 Journal-ref: Proceedings of the Physics Education Research conference, Rochester (Eds. K. Cummings, S. Franklin, J. Marx), 123-126, (2001) DOI: 10.1119/perc.2001.pr.018 \\ We investigate student understanding of energy and momentum concepts at the level of introductory physics by designing and administering a 25-item multiple choice test and conducting individual interviews. We find that most students have difficulty in qualitatively interpreting basic principles related to energy and momentum and in applying them in physical situations. The test development process and a summary of results are presented. \\ ( http://arxiv.org/abs/1602.07756 , 6kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07763 Date: Thu, 25 Feb 2016 01:24:20 GMT (1553kb) Title: Optimizing the robustness of electrical power systems against cascading failures Authors: Yingrui Zhang and Osman Yagan Categories: physics.soc-ph cs.SI physics.data-an Comments: 18 pages including 2 pages of supplementary file, 5 figures \\ Electrical power systems are one of the most important infrastructures that support our society. However, their vulnerabilities have raised great concern recently due to several large-scale blackouts around the world. In this paper, we investigate the robustness of power systems against cascading failures initiated by a random attack. This is done under a simple yet useful model based on global and equal redistribution of load upon failures. We provide a complete understanding of system robustness by i) deriving an expression for the final system size as a function of the size of initial attacks; ii) deriving the critical attack size after which system breaks down completely; iii) showing that complete system breakdown takes place through a first-order (i.e., discontinuous) transition in terms of the attack size; and iv) establishing the optimal load-capacity distribution that maximizes robustness. In particular, we show that robustness is maximized when the difference between the capacity and initial load is the same for all lines; i.e., when all lines have the same redundant space regardless of their initial load. This is in contrast with the intuitive and commonly used setting where capacity of a line is a fixed factor of its initial load. \\ ( http://arxiv.org/abs/1602.07763 , 1553kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07765 Date: Thu, 25 Feb 2016 01:25:57 GMT (4725kb) Title: Design of Ultra-compact Graphene-based Superscatterers Authors: Rujiang Li, Bin Zheng, Xiao Lin, Ran Hao, Shisheng Lin, Wenyan Yin, Erping Li, and Hongsheng Chen Categories: physics.optics Comments: This paper has been accepted by IEEE Journal of Selected topics in Quantum Electronics \\ The energy-momentum dispersion relation is a fundamental property of plasmonic systems. In this paper, we show that the method of dispersion engineering can be used for the design of ultra-compact graphene-based superscatterers. Based on the Bohr model, the dispersion relation of the equivalent planar waveguide is engineered to enhance the scattering cross section of a dielectric cylinder. Bohr conditions with different orders are fulfilled in multiple dispersion curves at the same resonant frequency. Thus the resonance peaks from the first and second order scattering terms are overlapped in the deepsubwavelength scale by delicately tuning the gap thickness between two graphene layers. Using this ultra-compact graphene-based superscatterer, the scattering cross section of the dielectric cylinder can be enhanced by five orders of magnitude. \\ ( http://arxiv.org/abs/1602.07765 , 4725kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07788 Date: Thu, 25 Feb 2016 04:25:39 GMT (595kb) Title: Picometer-resolution dual-comb spectroscopy with a free-running fibre laser Authors: Xin Zhao, Guoqing Hu, Bofeng Zhao, Cui Li, Yingling Pan, Ya Liu, Takeshi Yasui, Zheng Zheng Categories: physics.optics physics.ins-det \\ Dual-comb spectroscopy utilizes two sets of comb lines with slightly different comb-tooth-spacings, and optical spectral information is acquired by measuring the radio-frequency beat notes between the sets of comb lines. It holds the promise as a real-time, high-resolution analytical spectroscopy tool for a range of important applications. However, the stringent requirement on the coherence between comb lines from two separate lasers and the sophisticated control system to achieve that have confined the technology to the top metrology laboratories. By replacing electronics with the law of physics in lasers, a much simpler, dual-comb spectroscopy scheme is demonstrated here using just one dual-wavelength, passively mode-locked fiber laser. Dual-comb pulses with a repetition-frequency difference determined by the intracavity dispersion are shown to be robust against common-mode cavity drifts and noises. As sufficiently low relative linewidth is maintained between two sets of comb lines, capability to resolve picometer-wide spectral features is demonstrated using the simplest data acquisition and processing system in an all-fiber setup without further active control. Possibility to use energy-efficient and compact free-running fiber lasers with small comb-tooth-spacings could bring a fundamental change in the paradigm of dual-comb spectroscopy. By drastically lowering its system complexity, the technology could be rendered affordable to a plethora of new applications. \\ ( http://arxiv.org/abs/1602.07788 , 595kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07789 Date: Thu, 25 Feb 2016 04:33:48 GMT (3608kb,D) Title: Time-resolved Measurement of Quadrupole Wake?elds in Corrugated Structures Authors: Chao Lu, Feichao Fu, Tao Jiang, Shengguang Liu, Libin Shi, Rui Wang, Lingrong Zhao, Pengfei Zhu, Zhen Zhang, and Dao Xiang Categories: physics.acc-ph \\ Corrugated structures have recently been widely used for manipulating electron beam longitudinal phase space and for producing THz radiation. Here we report on time-resolved measurements of the quadrupole wake?elds in planar corrugated structures. It is shown that while the time- dependent quadrupole wake?eld produced by a planar corrugated structure causes signi?cant growth in beam transverse emittance, it can be e?ectively canceled with a second corrugated structure with orthogonal orientation. The strengths of the time-dependent quadrupole wake?elds for various corrugated structure gaps are also measured and found to be in good agreement with theories. Our work should forward the applications of corrugated structures in many accelerator based scienti?c facilities. \\ ( http://arxiv.org/abs/1602.07789 , 3608kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07791 Date: Thu, 25 Feb 2016 04:38:00 GMT (3929kb) Title: Stimulated Raman Adiabatic Passage for Improved Performance of a Cold Atom Electron and Ion Source Authors: B. M. Sparkes, D. Murphy, R. J. Taylor, R. W. Spiers, A. J. McCulloch, R. E. Scholten Categories: physics.atom-ph quant-ph Comments: 8 pages, 6 figures \\ We experimentally implement high-efficiency coherent excitation to a Rydberg state using stimulated Raman adiabatic passage in a cold atom electron and ion source, leading to a peak efficiency of 85%, a 1.7 times improvement in excitation probability relative to incoherent pulsed-laser excitation. Using streak measurements and pulsed electric field ionization of the Rydberg atoms we demonstrate electron bunches with duration of 250 ps. High-efficiency excitation will increase source brightness, crucial for ultrafast electron diffraction experiments, while using coherent excitation to high-lying Rydberg states could allow for the reduction of internal bunch heating and the creation of a high-speed single ion source. \\ ( http://arxiv.org/abs/1602.07791 , 3929kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07823 Date: Thu, 25 Feb 2016 07:10:28 GMT (1824kb) Title: Generation of nonlinear vortex precursors Authors: Yue-Yue Chen, Xun-Li Feng, and Chengpu Liu Categories: physics.optics \\ We numerically study the propagation of a few-cycle pulse carrying orbital angular momentum (OAM) through a dense atomic system. Nonlinear precursors consisting of high-order vortex har- monics are generated in the transmitted field due to ultrafast Bloch oscillation. The nonlinear precursors survive to propagation effects and are well separated with the main pulse, which provide a straightforward way of measuring precursors. By the virtue of carrying high-order OAM, the obtained vortex precursors as information carriers have potential applications in optical informa- tion and communication fields where controllable loss, large information-carrying capacity and high speed communication are required. \\ ( http://arxiv.org/abs/1602.07823 , 1824kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07834 Date: Thu, 25 Feb 2016 07:52:22 GMT (317kb,D) Title: Fluctuation capture in non-polar gases and liquids Authors: D. G. Cocks and R. D. White Categories: physics.comp-ph cond-mat.stat-mech Comments: 7 pages, 4 figures \\ We present a new model to identify natural fluctuations in fluids, allowing us to describe localization phenomena in the transport of electrons, positrons and positronium through non-polar fluids. The theory contains no free parameters and allows for the calculation of capture cross sections $\sigma_{cap}(\epsilon)$ of light-particles in any non-polar fluid, required for non-equilibrium transport simulations. We postulate that localization occurs through large shallow traps before stable bound states are formed. Our results allow us to explain most of the experimental observations of changes in mobility and annihilation rates in the noble gases and liquids as well as make predictions for future experiments. Quantities which are currently inaccessible to experiment, such as positron mobilities, can be obtained from our theory. Unlike other theoretical approaches to localization, the outputs of our theory can be applied in non-equilibrium transport simulations and an extension to the determination of waiting time distributions for localized states is straight forward. \\ ( http://arxiv.org/abs/1602.07834 , 317kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07840 Date: Thu, 25 Feb 2016 08:21:05 GMT (2982kb) Title: Transition from non-sequential to sequential double ionisation in many-electron systems Authors: Michael G. Pullen, Benjamin Wolter, Xu Wang, Xiao-Min Tong, Michele Sclafani, Matthias Baudisch, Hugo Pires, Claus Dieter Schr\"oter, Joachim Ullrich, Thomas Pfeifer, Robert Moshammer, J. H. Eberly and Jens Biegert Categories: physics.atom-ph Comments: 12 pages overall, 5 pages of main text, 3 figures \\ Obtaining a detailed understanding of strong-field double ionisation of many-electron systems (heavy atoms and molecules) remains a challenging task. By comparing experimental and theoretical results in the mid-IR regime, we have unambiguously identified the transition from non-sequential (e,2e) to sequential double ionisation in Xe and shown that it occurs at an intensity below $10^{14}$ Wcm$^{-2}$. In addition, our data demonstrate that ionisation from the Xe 5s orbital is decisive at low intensities. Moreover, using the acetylene molecule, we propose how sequential double ionisation in the mid-IR can be used to study molecular dynamics and fragmentation on unprecedented few-femtosecond timescales. \\ ( http://arxiv.org/abs/1602.07840 , 2982kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07881 Date: Thu, 25 Feb 2016 10:55:27 GMT (8871kb,D) Title: Smoothed Particle Hydrodynamics modeling of granular column collapse Authors: Kamil Szewc Categories: physics.geo-ph physics.comp-ph physics.flu-dyn \\ The Smoothed Particle Hydrodynamics (SPH) is a particle-based, Lagrangian method for fluid-flow simulations. In this work, fundamental concepts of this method are first briefly recalled. Then, the ability to accurately model granular materials using an introduced visco-plastic constitutive rheological model is studied. For this purpose sets of numerical calculations (2D and 3D) of the fundamental problem of the collapse of initially vertical cylinders of granular materials are performed. The results of modeling of columns with different aspect ratios and different angles of internal friction are presented. The numerical outcomes are assessed not only with respect to the reference experimental data but also with respect to other numerical methods, namely the Distinct Element Method and the Finite Element Method. In order to improve the numerical efficiency of the method, the Graphics Processing Units implementation is presented and some related issues are discussed. It is believed that this study corresponds to a new application of SPH approaches for simulations of granular media and results reveal the interest of this method to capture fine details of processes of such complex problems as waves-seabed interactions. \\ ( http://arxiv.org/abs/1602.07881 , 8871kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07892 Date: Thu, 25 Feb 2016 11:48:17 GMT (31kb,D) Title: Phase Mixing of Relativistically Intense Longitudinal Wave Packets in a Cold Plasma Authors: Arghya Mukherjee, Sudip Sengupta Categories: physics.plasm-ph \\ The spatio-temporal evolution and breaking of relativistically intense wave packets in a cold homogeneous unmagnetized plasma has been studied analytically and numerically. A general expression for phase mixing time scale as a function of amplitude of the wave packet and width of the spectrum has been derived. Results have been compared with the existing formulae in literature. It is shown that phase mixing time scale crucially depends on the relative magnitude of the amplitude and dimensionless spectral width of the wave packet. Finally we have verified our results with respect to both the amplitude of the wave packet and width of the spectral using numerical simulations based on Dawson Sheet Model. \\ ( http://arxiv.org/abs/1602.07892 , 31kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07894 Date: Thu, 25 Feb 2016 11:59:39 GMT (337kb) Title: One laser pulse generates two photoacoustic signals Authors: Fei Gao, Xiaohua Feng, Yuanjin Zheng Categories: physics.optics \\ Photoacoustic sensing and imaging techniques have been studied widely to explore optical absorption contrast based on nanosecond laser illumination. In this paper, we report a long laser pulse induced dual photoacoustic (LDPA) nonlinear effect, which originates from unsatisfied stress and thermal confinements. Being different from conventional short laser pulse illumination, the proposed method utilizes a long square-profile laser pulse to induce dual photoacoustic signals. Without satisfying the stress confinement, the dual photoacoustic signals are generated following the positive and negative edges of the long laser pulse. More interestingly, the first expansion-induced photoacoustic signal exhibits positive waveform due to the initial sharp rising of temperature. On the contrary, the second contraction-induced photoacoustic signal exhibits exactly negative waveform due to the falling of temperature, as well as pulse-width-dependent, signal amplitude which is caused by the concurrent heat accumulation and thermal diffusion during the long laser illumination. A simple analytical model is derived to describe the generation of the dual photoacoustic pulses, incorporating Gruneisen saturation and thermal diffusion effect, which is experimentally proved. The LDPA nonlinear effect also enables many potential applications using a low-cost laser diode system. \\ ( http://arxiv.org/abs/1602.07894 , 337kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07898 Date: Thu, 25 Feb 2016 12:14:09 GMT (592kb,D) Title: Examination of the Feynman-Hibbs Approach in the Study of Ne$_N$-Coronene Clusters at Low Temperatures Authors: R. Rodr\'iguez-Cantano, R. P\'erez de Tudela, M. Bartolomei, M. I. Hern\'andez, J. Campos-Mart\'inez, T. Gonz\'alez-Lezana, P. Villarreal, J. Hern\'andez-Rojas and J. Bret\'on Categories: physics.atm-clus \\ Feynman-Hibbs (FH) effective potentials constitute an appealing approach for investigations of many-body systems at thermal equilibrium since they allow us to easily include quantum corrections within standard classical simulations. In this work we apply the FH formulation to the study of Ne$_N$-coronene clusters ($N=$ 1-4, 14) in the 2-14 K temperature range. Quadratic (FH2) and quartic (FH4) contributions to the effective potentials are built upon Ne-Ne and Ne-coronene analytical potentials. In particular, a new corrected expression for the FH4 effective potential is reported. FH2 and FH4 cluster energies and structures -obtained from energy optimization through a basin-hoping algorithm as well as classical Monte Carlo simulations- are reported and compared with reference path integral Monte Carlo calculations. For temperatures $T> \approx 4$ K, both FH2 and FH4 potentials are able to correct the purely classical calculations in a consistent way. However, the FH approach fails at lower temperatures, especially the quartic correction. It is thus crucial to assess the range of applicability of this formulation and, in particular, to apply the FH4 potentials with great caution. A simple model of $N$ isotropic harmonic oscillators allows us to propose a means of estimating the cut-off temperature for the validity of the method, which is found to increase with the number of atoms adsorbed on the coronene molecule. \\ ( http://arxiv.org/abs/1602.07898 , 592kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07902 Date: Thu, 25 Feb 2016 12:23:49 GMT (3315kb,D) Title: Is the motion of a single SPH particle droplet/solid physically correct? Authors: Kamil Szewc, Katarzyna Walczewska-Szewc, Micha{\l} Olejnik Categories: physics.comp-ph physics.flu-dyn \\ In recent years the Smoothed Particle Hydrodynamics (SPH) approach gained popularity in modeling multiphase and free-surface flows. In many situations, due to certain reasons, interface and free-surface fragmentation occurs. As a result single SPH particle solids/droplets of one phase can appear and travel through other phases. In this paper we investigate this issue focusing on a movement of such single SPH particles. The main questions we try to answer here are: is movement of such particles physically correct? What is its physical size? How numerical parameters affect on it? With this in mind we performed simple simulations of solid particles falling due to gravity in a fluid. Considering three different diameters of a single particle, we compared values of the drag coefficient and the velocity obtained through the SPH approach with the experimental and the analytical reference data. In the way to accurately model multiphase flows with free-surfaces we proposed and validated a novel SPH formulation. \\ ( http://arxiv.org/abs/1602.07902 , 3315kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07904 Date: Thu, 25 Feb 2016 12:35:41 GMT (131kb) Title: Supplementary Conjugated Circuits for Biphenylene and related hydrocarbons Authors: Viktorija Gineityte Categories: physics.chem-ph \\ Individual Kekule valence structures of biphenylene and related hydrocarbons are comparatively studied in respect of their total pi-electron energies and thereby relative stabilities. These structures are modeled as sets of weakly-interacting initially-double (C=C) bonds. The relevant total energies are represented in the form of power series, wherein the averaged resonance parameter of initially-single (C-C) bonds underlies the expansion. To rationalize the resulting distinctions in total energies, interrelations are sought between separate members of the series, on the one hand, and presence of definite substructures in the given Kekule valence structure, on the other hand. It is shown that monocycles S_1 and S_2 correspondingly containing two and four exocyclic methylene groups (like 3,4-dimethylene cyclobutene and [4]radialene) participate in the formation of energy corrections of the relevant Kekule valence structures along with the usual conjugated circuits of the 4n+2 and 4n series (R_n and Q_n, n=1,2,3...). Thus, the cycles S_1 and S_2 are deductively predicted to play the role of supplementary conjugated circuits for biphenylene-like hydrocarbons. Moreover, the S_2- and S_1- containing structures are shown to be the most stable ones among all Kekule valence structures of the given hydrocarbon. Meanwhile, the lowest stability is predicted for structures in which either the neighboring hexagonal rings are connected by two C=C bonds or two exocyclic C=C bonds are attached to the same hexagonal ring. \\ ( http://arxiv.org/abs/1602.07904 , 131kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07913 Date: Thu, 25 Feb 2016 12:49:48 GMT (4496kb,D) Title: Comments on `Spurious interface fragmentation in multiphase SPH' by Szewc et al Authors: Kamil Szewc, Micha{\l} Tadeusz Lewandowski Categories: physics.comp-ph physics.flu-dyn \\ This article is a commentary on the paper `Spurious interface fragmentation in multiphase SPH', IJNME (2015) 103, pp. 625-649 [1]. In that paper, the authors presented detailed analysis of the problem of spurious interface fragmentation phenomena in Smoothed Particle Hydrodynamics method. After other researchers, in order to remove arising instabilities, the authors introduced the interface correction procedure. In this paper we show that the interface instabilities are physical and the introduction of the interface correction procedure may leads to non-physical solutions. We also explain the puzzling relation between the parameters " and h. The analysis is performed on the basis of the stability analysis and numerical calculations using SPH and Volume Of Fluid (VOF) approach. \\ ( http://arxiv.org/abs/1602.07913 , 4496kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07915 Date: Thu, 25 Feb 2016 12:56:58 GMT (613kb) Title: Correlated photon pair generation in low-loss double-stripe silicon nitride waveguides Authors: Xiang Zhang, Yanbing Zhang, Chunle Xiong and Benjamin J. Eggleton Categories: physics.optics Comments: 7 pages, 4 figures \\ We demonstrate correlated photon pair generation via spontaneous four-wave mixing in a low-loss double-stripe silicon nitride waveguide with a coincidence-to-accidental ratio over 10. The coincidence-to-accidental ratio is limited by spontaneous Raman scattering, which can be mitigated by cooling in the future. This demonstration suggests that this waveguide structure is a potential platform to develop integrated quantum photonic chips for quantum information processing. \\ ( http://arxiv.org/abs/1602.07915 , 613kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07918 Date: Thu, 25 Feb 2016 13:01:40 GMT (707kb) Title: Transverse beam size measurement system using visible synchrotron radiation at HLS II Authors: Kai Tang, Bao-Gen Sun, Yong-Liang Yang, Ping Lu, Lei-Lei Tang, Fang-Fang Wu, Chao-Cai Cheng, Jia-Jun Zheng, Hao Li Categories: physics.acc-ph Comments: 6 pages, 9 figures, 2 tables \\ An interferometer system and an imaging system using visible synchrotron radiation (SR) have been installed in HLS II storage ring. Simulations of these two systems are given using Synchrotron Radiation Workshop(SRW) code. With these two systems, the beam energy spread and the beam emittance can be measured. A detailed description of these two systems and the measurement method is given in this paper. The measurement results of beam size, emittance and energy spread are given at the end. \\ ( http://arxiv.org/abs/1602.07918 , 707kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07923 Date: Thu, 25 Feb 2016 13:26:36 GMT (70kb) Title: General Spin Precession and Betatron Oscillation in Storage Ring Authors: Takeshi Fukuyama Categories: physics.acc-ph hep-ph Comments: 8 pages, two figures \\ We give the geralized expression of spin precession of extended bunch particles having both anomalous magnetic and electric dipole moments in storage ring. The transversal betatron oscillation formula of the bunch is also given. The latter is the generalization of the Farley's pitch correction \cite{Farley}, including radial oscillation as well as vertical one. Some useful formulae for muon storage ring are discussed in appendix. \\ ( http://arxiv.org/abs/1602.07923 , 70kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07937 Date: Thu, 25 Feb 2016 14:00:19 GMT (5909kb,D) Title: Controlled uniform coating from the interplay of Marangoni flows and surface-adsorbed macromolecules Authors: Hyoungsoo Kim and Fran\c{c}ois Boulogne and Eujin Um and Ian Jacobi and Ernie Button and Howard A. Stone Categories: physics.flu-dyn cond-mat.soft \\ Surface coatings and patterning technologies are essential for various physicochemical applications. In this Letter, we describe key parameters to achieve uniform particle coatings in binary solutions: First, multiple sequential Marangoni flows, set by solute and surfactant simultaneously, prevent non-uniform particle distributions and continuously mix suspended materials during droplet evaporation. Second, we show the importance of particle-surface interactions that can be established by surface-adsorbed macromolecules. To achieve a uniform deposit in a binary mixture a small concentration of surfactant and surface-adsorbed polymer (0.05 wt% each) is sufficient, which offers a new physicochemical avenue for control of coatings. \\ ( http://arxiv.org/abs/1602.07937 , 5909kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07940 Date: Thu, 25 Feb 2016 14:17:00 GMT (52kb,D) Title: The scaling of the minimum sum of edge lengths in uniformly random trees Authors: Juan Luis Esteban, Ramon Ferrer-i-Cancho and Carlos G\'omez-Rodr\'iguez Categories: physics.data-an cs.DM physics.soc-ph \\ The minimum linear arrangement problem on a network consists of finding the minimum sum of edge lengths that can be achieved when the vertices are arranged linearly. Although there are algorithms to solve this problem on trees in polynomial time, they have remained theoretical and have not been implemented in practical contexts to our knowledge. Here we use one of those algorithms to investigate the growth of this sum as a function of the size of the tree in uniformly random trees. We show that this sum is bounded above by its value in a star tree. We also show that the mean edge length grows logarithmically in optimal linear arrangements, in stark contrast to the linear growth that is expected on optimal arrangements of star trees or on random linear arrangements. \\ ( http://arxiv.org/abs/1602.07940 , 52kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07949 Date: Thu, 25 Feb 2016 14:40:50 GMT (3198kb,D) Title: Electric fields, weighting fields, signals and charge diffusion in detectors including resistive materials Authors: Werner Riegler Categories: physics.ins-det \\ In this report we discuss static and time dependent electric fields in detector geometries with an arbitrary number of parallel layers of a given permittivity and weak conductivity. We derive the Green's functions i.e. the field of a point charge, as well as the weighting fields for readout pads and readout strips in these geometries. The effect of 'bulk' resistivity on electric fields and signals is investigated. The spreading of charge on thin resistive layers is also discussed in detail, and the conditions for allowing the effect to be described by the diffusion equation is discussed. We apply the results to derive fields and induced signals in Resistive Plate Chambers, Micromega detectors including resistive layers for charge spreading and discharge protection as well as detectors using resistive charge division readout like the MicroCAT detector. We also discuss in detail how resistive layers affect signal shapes and increase crosstalk between readout electrodes. \\ ( http://arxiv.org/abs/1602.07949 , 3198kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07958 Date: Thu, 25 Feb 2016 15:06:03 GMT (751kb) Title: Upholding the diffraction limit in the focusing of light and sound Authors: A. A. Maznev and O. B. Wright Categories: physics.optics \\ The concept of the diffraction limit put forth by Ernst Abbe and others has been an important guiding principle limiting our ability to tightly focus classical waves, such as light and sound, in the far field. In the past decade, numerous reports have described focusing or imaging with light and sound "below the diffraction limit". We argue that the diffraction limit defined in a reasonable way, for example in terms of the upper bound on the wave numbers corresponding to the spatial Fourier components of the intensity profile, or in terms of the spot size into which at least 50% of the incident power can be focused, still stands unbroken to this day. We review experimental observations of "subwavelength" or "sub-diffraction-limit" focusing, which can be principally broken down into three broad categories: (i) "super-resolution", i.e. the technique based on the modification of the pupil of the optical system to reduce the width of the central maximum in the intensity distribution at the expense of increasing side bands; (ii) solid immersion lenses, making use of metamaterials with a high effective index; (iii) concentration of intensity by a subwavelength structure such as an antenna. Even though a lot of interesting work has been done along these lines, none of the hitherto performed experiments violated the sensibly defined diffraction limit. \\ ( http://arxiv.org/abs/1602.07958 , 751kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07959 Date: Thu, 25 Feb 2016 15:06:46 GMT (8kb) Title: Configurational space continuity and free energy calculations Authors: Pu Tian Categories: physics.chem-ph Comments: 8 pages \\ Free energy is arguably the most importance function(al) for understanding of molecular systems. A number of rigorous and approximate free energy calculation/estimation methods have been developed over many decades. One important issue, the continuity of an interested macrostate (or path) in configurational space, has not been well articulated, however. As a matter of fact, some important special cases have been intensively discussed. In this perspective, I discuss the relevance of configurational space continuity in development of more efficient and reliable next generation free energy methodologies. \\ ( http://arxiv.org/abs/1602.07959 , 8kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07979 Date: Thu, 18 Feb 2016 15:15:42 GMT (5kb) Title: Octonionic geometry and conformal transformations Authors: Merab Gogberashvili Categories: physics.gen-ph gr-qc Comments: 5 pages, no figures \\ We describe space-time using split octonions over the reals and use their group of automorphisms, the non-compact form of Cartan's exceptional Lie group G2, as the main geometrical group of the model. It is studied connections of the G2-rotations of octonionic 8D space with the conformal transformations in 4D Minkowski space-time. It is shown that the dimensional constant needed in these analysis naturally gives the observed value of the cosmological constant. \\ ( http://arxiv.org/abs/1602.07979 , 5kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07991 Date: Thu, 25 Feb 2016 16:47:26 GMT (185kb) Title: Mode matching in second order susceptibility metamaterials Authors: S\'ebastien H\'eron and Patrick Bouchon and Riad Ha\"idar Categories: physics.optics \\ We present an effective model for a subwavelength periodically patterned metallic layer, its cavities being filled with a nonlinear dielectric material, which accounts for both the linear and second order behavior. The effective non linear susceptibility for the homogenized layer is driven by the nonlinearity of the dielectric material and by the geometrical parameters, thus leading to much higher susceptibility than existing materials. This leads to a huge enhancement of non linear processes when used together with resonances. Furthermore, multiple resonances are taking place in the metallic cavities, and we investigate the mode matching situations for frequency conversion processes and show how it enhances further their efficiency. \\ ( http://arxiv.org/abs/1602.07991 , 185kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07997 Date: Thu, 25 Feb 2016 17:16:15 GMT (225kb,D) Title: GPU performance analysis of a nodal discontinuous Galerkin method for acoustic and elastic models Authors: Axel Modave, Amik St-Cyr, Tim Warburton Categories: physics.comp-ph Comments: Paper submitted to Computers & Geosciences, 21 pages \\ Finite element schemes based on discontinuous Galerkin methods possess features amenable to massively parallel computing accelerated with general purpose graphics processing units (GPUs). However, the computational performance of such schemes strongly depends on their implementation. In the past, several implementation strategies have been proposed. They are based exclusively on specialized compute kernels tuned for each operation, or they can leverage BLAS libraries that provide optimized routines for basic linear algebra operations. In this paper, we present and analyze up-to-date performance results for different implementations, tested in a unified framework on a single NVIDIA GTX980 GPU. We show that specialized kernels written with a one-node-per-thread strategy are competitive for polynomial bases up to the fifth and seventh degrees for acoustic and elastic models, respectively. For higher degrees, a strategy that makes use of the NVIDIA cuBLAS library provides better results, able to reach a net arithmetic throughput 35.7% of the theoretical peak value. \\ ( http://arxiv.org/abs/1602.07997 , 225kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08001 Date: Thu, 25 Feb 2016 17:21:07 GMT (369kb) Title: Guiding of positive streamers in nitrogen, argon and N$_{2}$-O$_{2}$ mixtures by very low $n_{e}$ laser-induced pre-ionization trails Authors: S. Nijdam, E. Takahashi Categories: physics.plasm-ph Comments: 32nd International Conference of Phenomena in Ionized Gases, July 26 - 31, 2015, Iasi, Romania, Poster P4.19, 3 pages, 5 figures \\ In previous work we have shown that positive streamers in pure nitrogen can be guided by a laser-induced trail of low electron density. Here we show more detailed results from such measurements. We show the sensitivity of this laser-guiding on pressure p and found that the maximum delay between the laser pulse and voltage pulse for guiding scales with something between $1/p$ and $1/p^{2}$. We also show that when we use a narrower laser beam the laser guiding occurs less frequent and that when we move the laser beam away from the symmetry axis, guiding hardly is observed. Finally we show that laser guiding can also occur in pure argon. \\ ( http://arxiv.org/abs/1602.08001 , 369kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08005 Date: Thu, 25 Feb 2016 17:27:29 GMT (568kb,D) Title: Average Energy Expended Per e-h Pair and Energy Scale Function for Germanium-Based Dark Matter Experiments Authors: W.-Z. Wei, L. Wang, D.-M. Mei Categories: physics.ins-det hep-ex Comments: 18 pages, 8 figures \\ We report a new method to determine the temperature-dependent average energy expended per electron-hole (e-h) pair, $\varepsilon$, for germanium detectors. As a result, the Fano factor and $\varepsilon$ can be determined separately. Subsequently, we illustrate the variation of $\varepsilon$ as a function of temperature. The impact of $\varepsilon$ on the energy threshold and energy scale for germanium detectors at a given temperature is evaluated. We demonstrate an absolute energy scale function of low-energy recoils for germanium detectors in the direct detection of dark matter particles. \\ ( http://arxiv.org/abs/1602.08005 , 568kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08015 Date: Thu, 25 Feb 2016 18:06:07 GMT (6kb) Title: Modeling helicity dissipation-rate equation Authors: Nobumitsu Yokoi Categories: physics.flu-dyn astro-ph.SR Comments: 6 pages, 0 figures, Progress in Turbulence VI DOI: 10.1007/978-3-319-29130-7_17 \\ Transport equation of the dissipation rate of turbulent helicity is derived with the aid of a statistical analytical closure theory of inhomogeneous turbulence. It is shown that an assumption on the helicity scaling with an algebraic relationship between the helicity and its dissipation rate leads to the transport equation of the turbulent helicity dissipation rate without resorting to a heuristic modeling. \\ ( http://arxiv.org/abs/1602.08015 , 6kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08026 Date: Thu, 25 Feb 2016 18:23:40 GMT (124kb) Title: Enhancement of Ultracold Molecule Formation Using Shaped Nanosecond Frequency Chirps Authors: J. L. Carini, S. Kallush, R. Kosloff, and P. L. Gould Categories: physics.atom-ph Journal-ref: Phys. Rev. Lett. 115, 173003 (2015) DOI: 10.1103/PhysRevLett.115.173003 \\ We demonstrate that judicious shaping of a nanosecond-time-scale frequency chirp can dramatically enhance the formation rate of ultracold $^{87}$Rb$_{2}$ molecules. Starting with ultracold $^{87}$Rb atoms, we apply pulses of frequency-chirped light to first photoassociate the atoms into excited molecules and then, later in the chirp, de-excite these molecules into a high vibrational level of the lowest triplet state, $a \, ^{3}\Sigma_{u}^{+}$. The enhancing chirp shape passes through the absorption and stimulated emission transitions relatively slowly, thus increasing their adiabaticity, but jumps quickly between them to minimize the effects of spontaneous emission. Comparisons with quantum simulations for various chirp shapes support this enhancement mechanism. \\ ( http://arxiv.org/abs/1602.08026 , 124kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08030 Date: Thu, 25 Feb 2016 18:45:31 GMT (66kb,D) Title: A Response to arXiv:1512.09181, "Space Charge Limits in the DAEdALUS DIC Compact Cyclotron" Authors: Janet M. Conrad, Mike H. Shaevitz, Andreas Adelmann, Jose Alonso, Luciano Calabretta, and Daniel Winklehner, for the DAEdALUS collaboration Categories: physics.acc-ph \\ This document addresses concerns raised about possible limits, due to space charge, to the maximum H2+ ion beam current that can be injected into and accepted by a compact cyclotron. The discussion of the compact cyclotron is primarily within the context of the proposed DAEdALUS and IsoDAR neutrino experiments. These concerns are examined by the collaboration and addressed individually. While some of the concerns are valid, and present serious challenges to the proposed program, the collaboration sees no immediate showstoppers. However, some of the issues raised clearly need to be addressed carefully--analytically, through simulation, and through experiments. In this report, the matter is discussed, references are given to work already done and future plans are outlined. \\ ( http://arxiv.org/abs/1602.08030 , 66kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08039 Date: Thu, 25 Feb 2016 19:10:21 GMT (26kb) Title: A note on the notion "statistical symmetry" Authors: Michael Frewer, George Khujadze, Holger Foysi Categories: physics.flu-dyn cond-mat.stat-mech Comments: 8 pages \\ A critical review is presented on the most recent attempt to generally explain the notion of "statistical symmetry". This particular explanation, however, is incomplete and misses one important and essential aspect. The aim of this short note is to provide this missing information and to clarify this notion on the basis of a few instructive examples. \\ ( http://arxiv.org/abs/1602.08039 , 26kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08057 Date: Thu, 25 Feb 2016 19:44:28 GMT (8505kb,D) Title: Biphoton statistic of quantum light generated on a silicon chip Authors: Xiyuan Lu, Wei C. Jiang, Jidong Zhang, and Qiang Lin Categories: physics.optics quant-ph Comments: 11 pages, 10 figures \\ We demonstrate a silicon-chip biphoton source with an unprecedented quantum cross correlation up to ${\rm g_{si}^{(2)}(0) = (2.58 \pm 0.16) \times 10^4}$. The emitted biphotons are intrinsically single-mode, with self correlations of ${\rm g_{ss}^{(2)}(0) = 1.90 \pm 0.05}$ and ${\rm g_{ii}^{(2)}(0) = 1.87 \pm 0.06}$ for signal and idler photons, respectively. We observe the waveform asymmetry of cross correlation between signal and idler photons and reveal the identical and non-exponential nature of self correlations of individual signal and idler photon modes, which is a nature of cavity-enhanced nonlinear optical processes. The high efficiency and high purity of the biphoton source allow us to herald single photons with a conditional self correlation $\rm g_{c}^{(2)}(0)$ as low as $\rm 0.0059 \pm 0.0014$ at a pair flux of $\rm 1.95 \times 10^5$ pairs/s, which remains below $\rm 0.026 \pm 0.001$ for a biphoton flux up to $\rm 2.93 \times 10^6$ pairs/s, with a photon preparation efficiency in the single-mode fiber up to 51%, among the best values that have ever been reported. Our work unambiguously demonstrates that silicon photonic chips are superior material and device platforms for integrated quantum photonics. \\ ( http://arxiv.org/abs/1602.08057 , 8505kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08071 Date: Thu, 25 Feb 2016 20:26:40 GMT (789kb) Title: Enhanced X-ray-phase-contrast-tomography brings new clarity to the 2000-year-old 'voice' of Epicurean philosopher Philodemus Authors: I. Bukreeva, A. Mittone, A. Bravin, G. Festa, M. Alessandrelli, P. Coan, V. Formoso, R. G. Agostino, M. Giocondo, F. Ciuchi, M. Fratini, L. Massimi, A. Lamarra, C. Andreani, R. Bartolino, G. Gigli, G. Ranocchia, A. Cedola Categories: physics.soc-ph \\ A collection of more than 1800 carbonized Greek and Latin papyri, discovered in the Roman Villa dei Papiri at Herculaneum in the middle of 18th century, is the unique classical library survived from antiquity. These ancient-Herculaneum-papyri were charred during 79 A.D. Vesuvius eruption, a circumstance which providentially preserved them until now. This magnificent collection contains valuable work by Greek philosophers, such as Epicurus, Chrysippus and Philodemus, in particular an impressive amount of extensive treatises by Philodemus of Gadara, an Epicurean philosopher of the 1st century BC. The aim of the present study is to read extended and hitherto unknown portions of text hidden inside carbonized-Herculaneum-papyri using enhanced X-ray-phase-contrast-tomography (XPCT) non-destructive technique and a new set of numerical algorithms for virtual-unrolling. This paper documents our success in revealing the largest portion of Greek text ever detected so far inside unopened scrolls, with unprecedented spatial resolution and contrast, all without damaging these precious historical manuscripts. Parts of texts have been decoded and the 'voice' of Epicurean philosopher Philodemus is brought back again after 2000 years from rolled-up carbonized Herculaneum-papyri. \\ ( http://arxiv.org/abs/1602.08071 , 789kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08080 Date: Wed, 24 Feb 2016 16:48:14 GMT (3798kb,D) Title: A Bayesian approach for energy-based estimation of acoustic aberrations in high intensity focused ultrasound treatment Authors: Bamdad Hosseini, Charles Mougenot, Samuel Pichardo, Elodie Constanciel, James M. Drake, John M. Stockie Categories: physics.med-ph stat.AP \\ High intensity focused ultrasound is a non-invasive method for treatment of diseased tissue that uses a beam of ultrasound in order to generate heat within a small volume. A common challenge in application of this technique is that heterogeneity of the biological medium can defocus the ultrasound beam. In this study, the problem of refocusing the beam is reduced to the Bayesian inverse problem of estimating the acoustic aberration due to the biological tissue from acoustic radiative force imaging data. The solution to this problem is a posterior probability density on the aberration which is sampled using a Metropolis-within-Gibbs algorithm. The framework is tested using both a synthetic and experimental dataset. This new approach has the ability to obtain a good estimate of the aberrations from a small dataset, as little as 32 sonication tests, which can lead to significant speedup in the treatment process. Furthermore, this framework is very flexible and can work with a wide range of sonication tests and so it can be used alongside existing energy-based techniques. \\ ( http://arxiv.org/abs/1602.08080 , 3798kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08081 Date: Thu, 19 Mar 2015 01:46:12 GMT (109kb,D) Title: Kinetic Theory of Positron-Impact Ionization in Gases Authors: G. J. Boyle and W. J. Tattersall and D. G. Cocks and S. Dujko and R. D. White Categories: physics.plasm-ph physics.atom-ph physics.med-ph Comments: 34 pages, 6 figures \\ A kinetic theory model is developed for positron-impact ionization (PII) with neutral, rarefied gases. Particular attention is given to the sharing of available energy between the post-ionization constituents. A simple model for the energy-partition function that qualitatively captures the physics of high-energy and near-threshold ionization is developed for PII, with free parameters that can be used to fit the model to experimental data. By applying the model to the measurements of Kover and Laricchia [1] for positrons in H2, the role of energy-partitioning in PII for positron thermalisation is studied. Although the overall thermalisation time is found to be relatively insensitive to the energy-partitioning, the mean energy profiles at certain times can differ by more than an order of magnitude for the various treatments of energy-partitioning. This can significantly impact the number and energy distribution of secondary electrons. \\ ( http://arxiv.org/abs/1602.08081 , 109kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08087 Date: Thu, 25 Feb 2016 20:53:21 GMT (1807kb,D) Title: Single envelope equation modelling of multi-octave comb arrays in microresonators with quadratic and cubic nonlinearity Authors: T. Hansson, F. Leo, M. Erkintalo, J. Anthony, S. Coen, I. Ricciardi, M. De Rosa and S. Wabnitz Categories: physics.optics \\ We numerically study, by means of the single envelope equation, the generation of optical frequency combs ranging from the visible to the mid-infrared spectral regions in resonators with quadratic and cubic nonlinearities. Phase-matched quadratic wave-mixing processes among the comb lines can be activated by low-power continuous wave pumping in the near infrared of a radially poled lithium niobate whispering gallery resonator (WGR). We examine both separate and co-existing intra-cavity doubly resonant second-harmonic generation and parametric oscillation processes, and find that modulation instabilities may lead to the formation of coupled comb arrays extending over multiple octaves. In the temporal domain, the frequency combs may correspond to pulse trains, or isolated pulses. \\ ( http://arxiv.org/abs/1602.08087 , 1807kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08090 Date: Thu, 25 Feb 2016 20:56:23 GMT (2182kb,D) Title: Volt-Ampere characteristic of "black box" with a negative resistance Authors: Stojan G. Manolev, Vasil G. Yordanov, Nikolay N. Tomchev, Todor M. Mishonov Categories: physics.ed-ph Comments: 55 pages, 47 figures. English, Bulgarian, Macedonian and Serbian translations \\ This problem was given at Third Experimental Physics Olympiad "The day of the resistor", 31 October 2015, Kumanovo, organized by the Regional Society of Physicists of Strumica, Macedonia and the Sofia Branch of the Union of Physicists in Bulgaria. \\ ( http://arxiv.org/abs/1602.08090 , 2182kb) %-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%- ------------------------------------------------------------------------------ \\ arXiv:1602.07498 (*cross-listing*) Date: Wed, 24 Feb 2016 13:36:19 GMT (4515kb,D) Title: Effective potential from zero-momentum potential Authors: Janos Balog and Pengming Zhang Categories: nucl-th physics.class-ph Comments: 24 pages, 10 figures MSC-class: 83C47, 70F05 \\ We obtain the centre-of-mass frame effective potential from the zero-momentum potential in Ruijsenaars-Schneider type 1-dimensional relativistic mechanics using classical inverse scattering methods. \\ ( http://arxiv.org/abs/1602.07498 , 4515kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07692 (*cross-listing*) Date: Wed, 24 Feb 2016 21:00:04 GMT (296kb) Title: Synchrotron Magnetic Fields from Rayleigh-Taylor Instability in Supernovae Authors: Paul Duffell, Daniel Kasen Categories: astro-ph.HE physics.flu-dyn \\ Synchrotron emission from a supernova necessitates a magnetic field, but it is unknown how strong the relevant magnetic fields are, and what mechanism generates them. In this study, we perform high-resolution numerical gas dynamics calculations to determine the growth of turbulence due to Rayleigh-Taylor instability, and the resulting kinetic energy in turbulent fluctuations, to infer the strength of magnetic fields amplified by this turbulence. We find that Rayleigh-Taylor instability can produce turbulent fluctuations strong enough to amplify magnetic fields to a few percent of equipartition with the thermal energy. This turbulence stays concentrated near the reverse shock, but averaging this magnetic energy throughout the shocked region (weighting by emissivity) sets the magnetic fields at a minimum of 0.3 percent of equipartition. This suggests a minimum effective magnetic field strength ($\epsilon_B > 0.003$) which should be present in all interacting supernovae. \\ ( http://arxiv.org/abs/1602.07692 , 296kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07703 (*cross-listing*) Date: Wed, 24 Feb 2016 21:01:06 GMT (5235kb,D) Title: Anisotropic Diffusion in Mesh-Free Numerical Magnetohydrodynamics Authors: Philip F. Hopkins (Caltech) Categories: astro-ph.IM astro-ph.SR physics.comp-ph Comments: 25 pages, 19 figures, MNRAS submitted. A public version of the GIZMO code is available at http://www.tapir.caltech.edu/~phopkins/Site/GIZMO.html \\ We extend recently-developed mesh-free Lagrangian methods for numerical magnetohydrodynamics (MHD) to arbitrary anisotropic diffusion equations, including: passive scalar diffusion, Spitzer-Braginskii conduction and viscosity, cosmic ray diffusion/streaming, anisotropic radiation transport, non-ideal MHD (Ohmic resistivity, ambipolar diffusion, the Hall effect), and turbulent 'eddy diffusion.' We study these as implemented in the code GIZMO for both new meshless finite-volume Godunov schemes (MFM/MFV) as well as smoothed-particle hydrodynamics (SPH). We show the MFM/MFV methods are accurate and stable even with noisy fields and irregular particle arrangements, and recover the correct behavior even in arbitrarily anisotropic cases. They are competitive with state-of-the-art AMR/moving-mesh methods, and can correctly treat anisotropic diffusion-driven instabilities (e.g. the MTI and HBI, Hall MRI). We also develop a new scheme for stabilizing anisotropic tensor-valued fluxes with high-order gradient estimators and non-linear flux limiters, which is trivially generalized to AMR/moving-mesh codes. We find that SPH is accurate for isotropic diffusion; however, fundamental errors in the most common SPH discretizations are either numerically unstable, or produce large systematic errors in anisotropic cases that do not converge. We develop a new integral-Godunov SPH formulation which resolves these errors by replacing the standard SPH gradient estimator with a moving least-squares estimator and solving a flux-limited Riemann problem between particles. However in problems with full MHD, well-known SPH errors can still swamp the physical diffusivity. \\ ( http://arxiv.org/abs/1602.07703 , 5235kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07741 (*cross-listing*) Date: Wed, 24 Feb 2016 22:55:05 GMT (853kb) Title: Sunspot Numbers from ISOON: A Ten-Year Data Analysis Authors: K. S. Balasubramaniam and T. W. Henry Categories: astro-ph.SR physics.space-ph Comments: 20 pages, including 10 figures in Solar Physics 2016 DOI: 10.1007/s11207-016-0874-5 \\ Sunspot numbers are important tracers of historical solar activity. They are important in the prediction of oncoming solar maximum, in the design of lifetimes of space assets, and in assessing the extent of solar-radiation impact on the space environment. Sunspot numbers were obtained visually from sunspot drawings. The availability of digital images from the US Air Force Improved Solar Optical Observing Network (ISOON) prototype telescope concurrent to observer-dependent sunspot numbers recorded at the National Solar Observatory (NSO) has provided a basis for comparing sunspot numbers determined from the two methods. We compare sunspot numbers from visual and digital methods observed nearly simultaneously. The advantages of digital imagery are illustrated. \\ ( http://arxiv.org/abs/1602.07741 , 853kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07742 (*cross-listing*) Date: Wed, 24 Feb 2016 22:55:54 GMT (2209kb,D) Title: Muon Flux Measurements at the Davis Campus of the Sanford Underground Research Facility with the {\sc Majorana Demonstrator} Veto System Authors: N. Abgrall, E. Aguayo, F.T. Avignone III, A.S. Barabash, F.E. Bertrand, A.W. Bradley, V. Brudanin, M. Busch, M. Buuck, D. Byram, A.S. Caldwell, Y-D. Chan, C.D. Christofferson, P.-H. Chu, C. Cuesta, J.A. Detwiler, C. Dunagan, Yu. Efremenko, H. Ejiri, S.R. Elliott, A. Galindo-Uribarri, T. Gilliss, G.K. Giovanetti, J. Goett, M.P. Green, J. Gruszko, I.S. Guinn, V.E. Guiseppe, R. Henning, E.W. Hoppe, S. Howard, M.A. Howe, B.R. Jasinski, K.J. Keeter, M.F. Kidd, S.I. Konovalov, R.T. Kouzes, B.D. LaFerriere, J. Leon, A.M. Lopez, J. MacMullin, R.D. Martin, R. Massarczyk, S.J. Meijer, S. Mertens, J.L. Orrell, C. O'Shaughnessy, N.R. Overman, A.W.P. Poon, D.C. Radford, J. Rager, K. Rielage, R.G.H. Robertson, E. Romero-Romero, M.C. Ronquest, C. Schmitt, B. Shanks, M. Shirchenko, N. Snyder, A.M. Suriano, D. Tedeschi, J.E. Trimble, R.L. Varner, S. Vasilyev, K. Vetter, K. Vorren, B.R. White, J.F. Wilkerson, C. Wiseman, W. Xu, E. Yakushev, C.-H. Yu, V. Yumatov, I. Zhitnikov (The Majorana Collaboration) Categories: nucl-ex physics.ins-det \\ We report the first measurement of the total MUON flux underground at the Davis Campus of the Sanford Underground Research Facility at the 4850 ft level. Measurements were done with the Majorana Demonstrator veto system arranged in two different configurations. The measured total flux is (5.04+/-0.16) x 10^-9 muons/s/cm^2. \\ ( http://arxiv.org/abs/1602.07742 , 2209kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07781 (*cross-listing*) Date: Thu, 25 Feb 2016 03:09:47 GMT (131kb,D) Title: A Markov chain model for the search time for max degree nodes in a graph using a biased random walk Authors: Jonathan Stokes and Steven Weber Categories: cs.SI cs.DM physics.soc-ph Comments: 7 pages, 7 figures, submitted to CISS 2016 \\ We consider the problem of estimating the expected time to find a maximum degree node on a graph using a (parameterized) biased random walk. For assortative graphs the positive degree correlation serves as a local gradient for which a bias towards selecting higher degree neighbors will on average reduce the search time. Unfortunately, although the expected absorption time on the graph can be written down using the theory of absorbing Markov chains, computing this time is infeasible for large graphs. With this motivation, we construct an absorbing Markov chain with a state for each degree of the graph, and observe computing the expected absorption time is now computationally feasible. Our paper finds preliminary results along the following lines: i) there are graphs for which the proposed Markov model does and graphs for which the model does not capture the absorbtion time, ii) there are graphs where random sampling outperforms biased random walks, and graphs where biased random walks are superior, and iii) the optimal bias parameter for the random walk is graph dependent, and we study the dependence on the graph assortativity. \\ ( http://arxiv.org/abs/1602.07781 , 131kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07786 (*cross-listing*) Date: Thu, 25 Feb 2016 04:00:31 GMT (244kb) Title: An electro-optic waveform interconnect based on quantum interference Authors: Li-Guo Qin, Zhong-Yang Wang, and Shang-Qing Gong Categories: quant-ph physics.optics \\ The ability to modulate an optical field via an electric field is regarded as a key function of electro-optic interconnects, which are used in optical communications and information processing systems. One of the main required devices for such interconnects is the electro-optic modulator (EOM). Current EOM based on the electro-optic effect and the electro-absorption effect often is bulky and power inefficient due to the weak electro-optic properties of its constituent materials. Here we propose a new mechanism to produce an arbitrary-waveform EOM based on the quantum interference, in which both the real and imaginary parts of the susceptibility are engineered coherently with the superhigh efficiency. Based on this EOM, a waveform interconnect from the voltage to the modulated optical absorption is realised. We expect that such a new type of electro-optic interconnect will have a broad range of applications including the optical communications and network. \\ ( http://arxiv.org/abs/1602.07786 , 244kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07801 (*cross-listing*) Date: Thu, 25 Feb 2016 05:18:27 GMT (20kb) Title: Investigating multi-channel quantum tunneling in heavy-ion fusion reactions with Bayesian spectral decomposition Authors: K. Hagino Categories: nucl-th nucl-ex physics.data-an Comments: 5 pages, 3 eps figures \\ Excitations of colliding nuclei during a nuclear reaction considerably affect fusion cross sections at energies around the Coulomb barrier. It has been demonstrated that such channel coupling effects can be represented in terms of a distribution of multiple fusion barriers. We here apply a Bayesian approach to analyze the so called fusion barrier distributions. This method determines simultaneously the barrier parameters and the number of barriers. We particularly investigate the $^{16}$O+$^{144}$Sm and $^{16}$O+$^{154}$Sm systems in order to demonstrate the effectiveness of the method. The present analysis indicates that the fusion barrier distribution for the former system is most consistent with three fusion barriers, even though the experimental data show only two distinct peaks. \\ ( http://arxiv.org/abs/1602.07801 , 20kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07832 (*cross-listing*) Date: Thu, 25 Feb 2016 07:43:49 GMT (440kb,D) Title: Manipulation of light in a generalized coupled Nonlinear Schrodinger equation Authors: R. Radha, P. S. Vinayagam and K. Porsezian Categories: cond-mat.quant-gas physics.optics Comments: Communications in Nonlinear Science and Numerical Simulation, In Press \\ We investigate a generalized coupled nonlinear Schrodinger (GCNLS) equation containing Self-Phase Modulation (SPM), Cross-Phase Modulation (XPM) and Four Wave Mixing (FWM) describing the propagation of electromagnetic radiation through an optical fibre and generate the associated Lax-pair. We then construct bright solitons employing gauge transformation approach. The collisional dynamics of bright solitons indicates that it is not only possible to manipulate intensity (energy) between the two modes (optical beams), but also within a given mode unlike the Manakov model which does not have the same freedom. The freedom to manipulate intensity (energy) in a given mode or between two modes arises due to a suitable combination of SPM, XPM and FWM.While SPM and XPM are controlled by an arbitrary real parameter each, FWM is governed by two arbitrary complex parameters. The above model may have wider ramifications in nonlinear optics and Bose-Einstein Condensates (BECs). \\ ( http://arxiv.org/abs/1602.07832 , 440kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07882 (*cross-listing*) Date: Thu, 25 Feb 2016 10:58:41 GMT (1524kb,D) Title: Nonequilibrium Green's functions and atom-surface dynamics: Simple views from a simple model system Authors: E. Bostr\"om, M. Hopjan, A. Kartsev, C. Verdozzi, C.-O. Almbladh Categories: cond-mat.mes-hall cond-mat.mtrl-sci physics.chem-ph Comments: 10 pages, 5 figures \\ We employ Non-equilibrium Green's functions (NEGF) to describe the real-time dynamics of an adsorbate-surface model system exposed to ultrafast laser pulses. For a finite number of electronic orbitals, the system is solved exactly and within different levels of approximation. Specifically i) the full exact quantum mechanical solution for electron and nuclear degrees of freedom is used to benchmark ii) the Ehrenfest approximation (EA) for the nuclei, with the electron dynamics still treated exactly. Then, using the EA, electronic correlations are treated with NEGF within iii) 2nd Born and with iv) a recently introduced hybrid scheme, which mixes 2nd Born self-energies with non-perturbative, local exchange-correlation potentials of Density Functional Theory (DFT). Finally, the effect of a semi-infinite substrate is considered: we observe that a macroscopic number of de-excitation channels can hinder desorption. While very preliminary in character and based on a simple and rather specific model system, our results clearly illustrate the large potential of NEGF to investigate atomic desorption, and more generally, the non equilibrium dynamics of material surfaces subject to ultrafast laser fields. \\ ( http://arxiv.org/abs/1602.07882 , 1524kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07883 (*cross-listing*) Date: Thu, 25 Feb 2016 11:01:07 GMT (599kb,D) Title: The Efficiency of Self-Phoretic Propulsion Mechanisms with Surface Reaction Heterogeneity Authors: Patrick Kreissl, Christian Holm, Joost de Graaf Categories: cond-mat.soft physics.flu-dyn Comments: 10 pages, 4 figures \\ We consider the efficiency of self-phoretic colloidal particles (swimmers) as a function of the heterogeneity in the surface reaction rate. The set of fluid, species, and electrostatic continuity equations is solved analytically using a linearization and numerically using a finite-element method. To compare spherical swimmers of different size and with heterogeneous catalytic conversion rates, a 'swimmer efficiency' functional $\eta$ is introduced. It is proven, that in order to obtain maximum swimmer efficiency the reactivity has to be localized at the pole(s). Our results also shed light on the sensitivity of the propulsion speed to details of the surface reactivity, a property that is notoriously hard to measure. This insight can be utilized in the design of new self-phoretic swimmers. \\ ( http://arxiv.org/abs/1602.07883 , 599kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07928 (*cross-listing*) Date: Thu, 25 Feb 2016 13:39:49 GMT (316kb) Title: Recognition of Emerging Technology Trends. Class-selective study of citations in the U.S. Patent Citation Network Authors: P\'eter Bruck, Istv\'an R\'ethy, Judit Szente, Jan Tobochnik, P\'eter \'Erdi Categories: cs.DL physics.soc-ph Comments: 8 pages, 2 tables, 1 figure , (accepted). in Scientometrics 2016 \\ By adopting a citation-based recursive ranking method for patents the evolution of new fields of technology can be traced. Specifically, it is demonstrated that the laser / inkjet printer technology emerged from the recombination of two existing technologies: sequential printing and static image production. The dynamics of the citations coming from the different "precursor" classes illuminates the mechanism of the emergence of new fields and give the possibility to make predictions about future technological development. For the patent network the optimal value of the PageRank damping factor is close to 0.5; the application of d=0.85 leads to unacceptable ranking results. \\ ( http://arxiv.org/abs/1602.07928 , 316kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07964 (*cross-listing*) Date: Thu, 25 Feb 2016 15:31:13 GMT (648kb) Title: Non-Scanning Fiber-Optic Near-Infrared Beam Led to Two-Photon Optogenetic Stimulation In-Vivo Authors: Kamal R. Dhakal, Ling Gu, Shivaranjani Shivalingaiah, Torry S. Dennis, Samara A. Morris-Bobzean, Ting Li, Linda I. Perrotti, Samarendra K. Mohanty Categories: q-bio.CB physics.optics Comments: November 10, 2014 Journal-ref: PLoS ONE 9(11): e111488 DOI: 10.1371/journal.pone.0111488 \\ Stimulation of specific neurons expressing opsins in a targeted region to manipulate brain function has proved to be a powerful tool in neuroscience. However, the use of visible light for optogenetic stimulation is invasive due to low penetration depth and tissue damage owing to larger absorption and scattering. Here, we report, for the first time, in-depth non-scanning fiber-optic two-photon optogenetic stimulation (FO-TPOS) of neurons in-vivo in transgenic mouse models. In order to optimize the deep-brain stimulation strategy, we characterized two-photon activation efficacy at different nearinfrared laser parameters. The significantly-enhanced in-depth stimulation efficiency of FO-TPOS as compared to conventional single-photon beam was demonstrated both by experiments and Monte Carlo simulation. The non-scanning FO-TPOS technology will lead to better understanding of the in-vivo neural circuitry because this technology permits more precise and less invasive anatomical delivery of stimulation. \\ ( http://arxiv.org/abs/1602.07964 , 648kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07969 (*cross-listing*) Date: Thu, 25 Feb 2016 15:40:12 GMT (1963kb) Title: Introduction of impermeable actin-staining molecules to mammalian cells by optoporation Authors: Kamal Dhakal, Bryan Black and Samarendra Mohanty Categories: q-bio.CB physics.bio-ph Comments: SCIENTIFIC REPORTS | 4 : 6553 | DOI: 10.1038/srep06553,15 October 2014 \\ The selective insertion of foreign materials, such as fluorescent markers or plasmids, into living cells has been a challenging problem in cell biology.However, it is often necessary that researchers insert such materials into cells for various dynamical and/or drug delivery studies. This problem becomes even more challenging if the study is to be limited to specific cells within a larger population, since other transfection methods, such as viral transfection and lipofection, are not realizable with a high degree of spatial selectivity.Here, we have used a focused femtosecond laser beam to create a small transient hole in the cellular membrane (optoporation) in order to inject nanomolar concentrations of rhodamine phalloidin (an impermeable dye molecule for staining filamentous actin) into targeted living mammalian cells (both HEK and primary cortical neurons).Following optoporation, the bound to the intracellular actin network and rise in fluorescence intensity was observed... \\ ( http://arxiv.org/abs/1602.07969 , 1963kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07974 (*cross-listing*) Date: Thu, 25 Feb 2016 16:04:15 GMT (3324kb,D) Title: Evaluation of selected recurrence measures in discriminating pre-ictal and inter-ictal periods from epileptic EEG data Authors: Eulalie Joelle Ngamga, Stephan Bialonski, Norbert Marwan, J\"urgen Kurths, Christian Geier, Klaus Lehnertz Categories: nlin.CD physics.data-an physics.med-ph Comments: 7 pages, 4 figures DOI: 10.1016/j.physleta.2016.02.024 \\ We investigate the suitability of selected measures of complexity based on recurrence quantification analysis and recurrence networks for an identification of pre-seizure states in multi-day, multi-channel, invasive electroencephalographic recordings from five epilepsy patients. We employ several statistical techniques to avoid spurious findings due to various influencing factors and due to multiple comparisons and observe precursory structures in three patients. Our findings indicate a high congruence among measures in identifying seizure precursors and emphasize the current notion of seizure generation in large-scale epileptic networks. A final judgment of the suitability for field studies, however, requires evaluation on a larger database. \\ ( http://arxiv.org/abs/1602.07974 , 3324kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08009 (*cross-listing*) Date: Thu, 25 Feb 2016 17:44:09 GMT (614kb,D) Title: Schr\"odinger Cat States Generated by Quantum Gated Photonic Gauge Field Authors: Da-Wei Wang, Han Cai, Ren-Bao Liu and Marlan O. Scully Categories: quant-ph cond-mat.mes-hall physics.atom-ph Comments: 5 pages, 2 figures \\ Schr\"odinger cat states of photons can be prepared by effective gauge fields gated by the quantum states of a two-level atom interacting with three cavities. By periodically modulating the cavity frequencies with different phases, opposite effective gauge fields of cavity photons can be created for the two quantum states of the atom. A superposition of atomic states can transport photons from one cavity to a macroscopic superposition of the other two cavities. This mechanism provides new possibilities in exploring quantum entanglement and has applications in quantum metrology and quantum information. \\ ( http://arxiv.org/abs/1602.08009 , 614kb) ------------------------------------------------------------------------------ \\ arXiv:1602.08078 (*cross-listing*) Date: Thu, 25 Feb 2016 20:40:03 GMT (3978kb) Title: Numerical computation of shape factor for pair distribution function of nanoparticles using atomistic model Authors: Dung-Trung Tran, Gunnar Svensson and Cheuk-Wai Tai Categories: cond-mat.mtrl-sci cond-mat.mes-hall cond-mat.other physics.comp-ph Comments: 22 pages, 8 figures and 1 table \\ The atomic pair distribution function (PDF) for nano-particles has to be corrected with a shape factor, also known as form factor, in order to take size and shape effects into consideration. For most anisotropic shapes an analytical formulation of the shape factor is a challenge. In this paper, we present a new method to numerically compute the shape factor using atomistic model. This numerical method to calculate PDF for a wide range of geometrical shapes is demonstrated. In addition, a fitting formulation, which effectively converts the numerical shape factors for some selected geometrical shapes to the analytical forms, is presented. \\ ( http://arxiv.org/abs/1602.08078 , 3978kb) %%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%% ------------------------------------------------------------------------------ \\ arXiv:1407.3611 replaced with revised version Thu, 25 Feb 2016 11:52:16 GMT (2159kb,D) Title: Mesoscopic Rydberg-blockaded ensembles in the superatom regime and beyond Authors: T. M. Weber, M. H\"oning, T. Niederpr\"um, T. Manthey, O. Thomas, V. Guarrera, M. Fleischhauer, G. Barontini and H. Ott Categories: physics.atom-ph cond-mat.quant-gas quant-ph Comments: 7 pages, 5 figures Journal-ref: Nature Physics 11, 157-161 (2015) DOI: 10.1038/nphys3214 \\ ( http://arxiv.org/abs/1407.3611 , 2159kb) ------------------------------------------------------------------------------ \\ arXiv:1408.1763 replaced with revised version Thu, 25 Feb 2016 16:03:55 GMT (2875kb,D) Title: Scintillation Light from Cosmic-Ray Muons in Liquid Argon Authors: Denver Whittington, Stuart Mufson, and Bruce Howard Categories: physics.ins-det hep-ex Comments: 30 pages, 10 figures. This experiment has been repeated with improved data quality and analysis techniques Report-no: FERMILAB-PUB-15-488-ND-PPD \\ ( http://arxiv.org/abs/1408.1763 , 2875kb) ------------------------------------------------------------------------------ \\ arXiv:1506.02810 replaced with revised version Thu, 25 Feb 2016 00:13:42 GMT (583kb) Title: Chandler wobble: Stochastic and deterministic dynamics Authors: Alejandro Jenkins Categories: physics.geo-ph nlin.AO physics.class-ph Comments: 10 pages, 3 figures. v2: Briefly clarified incompatibility of forced resonance model with estimated quality factor, improved references, adjustments to title and abstract, change of format. Presented at the 13th International Conference, Dynamical Systems - Theory and Applications (DSTA '2015), {\L}\'od\'z, Poland, 7-10 Dec. 2015 \\ ( http://arxiv.org/abs/1506.02810 , 583kb) ------------------------------------------------------------------------------ \\ arXiv:1507.01726 replaced with revised version Thu, 25 Feb 2016 09:27:23 GMT (75kb) Title: Optimization of synchronizability in multiplex networks Authors: Sanjiv K. Dwivedi, Camellia Sarkar and Sarika Jalan Categories: physics.soc-ph nlin.CD Comments: 6 pages and 6 figures Journal-ref: EPL 111, 10005 (2015) DOI: 10.1209/0295-5075/111/10005 \\ ( http://arxiv.org/abs/1507.01726 , 75kb) ------------------------------------------------------------------------------ \\ arXiv:1507.07275 (*cross-listing*) replaced with revised version Thu, 25 Feb 2016 03:08:40 GMT (3426kb) Title: Robust Intrinsic Ferromagnetism and Half Semiconductivity in Stable Two-Dimensional Single-Layer Chromium Trihalides Authors: Wei-Bing Zhang, Qian Qu, Peng Zhu, and Chi-Hang Lam Categories: cond-mat.mtrl-sci physics.comp-ph Comments: 12 pages, 14 figures. published in J. Mater. Chem. C Journal-ref: J. Mater. Chem. C 3, 12457 (2015) DOI: 10.1039/c5tc02840j \\ ( http://arxiv.org/abs/1507.07275 , 3426kb) ------------------------------------------------------------------------------ \\ arXiv:1507.07334 replaced with revised version Thu, 25 Feb 2016 09:58:50 GMT (4595kb,D) Title: Sliding without slipping under Coulomb friction: opening waves and inversion of frictional force Authors: Vladislav A. Yastrebov Categories: physics.geo-ph Comments: 17 pages, 4 figures, 1 table Journal-ref: Tribology Letters 62(1):1-8 (2016) DOI: 10.1007/s11249-016-0650-6 \\ ( http://arxiv.org/abs/1507.07334 , 4595kb) ------------------------------------------------------------------------------ \\ arXiv:1508.00760 replaced with revised version Thu, 25 Feb 2016 14:55:37 GMT (295kb,D) Title: Attosecond photoionization dynamics with stimulated core-valence transitions Authors: Jhih-An You and Nina Rohringer and Jan Marcus Dahlstr\"om Categories: physics.atom-ph Comments: 12 pages, 5 figures \\ ( http://arxiv.org/abs/1508.00760 , 295kb) ------------------------------------------------------------------------------ \\ arXiv:1508.01162 (*cross-listing*) replaced with revised version Thu, 25 Feb 2016 12:32:57 GMT (2372kb) Title: Implementation of Resistive Type Superconducting Fault Current Limiters in Electrical Grids: Performance Analysis and Measuring of Optimal Locations Authors: Xiuchang Zhang, H. S. Ruiz, Z. Zhong, and T. A. Coombs Categories: cond-mat.supr-con cs.SY physics.ins-det \\ ( http://arxiv.org/abs/1508.01162 , 2372kb) ------------------------------------------------------------------------------ \\ arXiv:1508.02159 replaced with revised version Wed, 24 Feb 2016 22:33:19 GMT (1724kb,D) Title: Filling transitions on rough surfaces: inadequacy of Gaussian surface models Authors: Renaud Dufour, Ciro Semprebon, Stephan Herminghaus Categories: physics.flu-dyn \\ ( http://arxiv.org/abs/1508.02159 , 1724kb) ------------------------------------------------------------------------------ \\ arXiv:1508.04629 (*cross-listing*) replaced with revised version Thu, 25 Feb 2016 10:16:45 GMT (0kb,I) Title: On the characterization of integrable systems via the Haantjes geometry Authors: Piergiulio Tempesta and Giorgio Tondo Categories: math-ph math.MP nlin.SI physics.class-ph Comments: This manuscript has been merged with the paper "Haantjes manifolds of classical integrable systems", arXiv:1405.5118 \\ ( http://arxiv.org/abs/1508.04629 , 0kb) ------------------------------------------------------------------------------ \\ arXiv:1509.06624 (*cross-listing*) replaced with revised version Thu, 25 Feb 2016 10:46:25 GMT (342kb,D) Title: Parallel transport quantum logic gates with trapped ions Authors: Ludwig E. de Clercq, Hsiang-Yu Lo, Matteo Marinelli, David Nadlinger, Robin Oswald, Vlad Negnevitsky, Daniel Kienzler, Ben Keitch, Jonathan P. Home Categories: quant-ph physics.atom-ph physics.optics Comments: 5 pages, 4 figures, shorten the text and modify the figures Journal-ref: Phys. Rev. Lett. 116, 080502 (2016) DOI: 10.1103/PhysRevLett.116.080502 \\ ( http://arxiv.org/abs/1509.06624 , 342kb) ------------------------------------------------------------------------------ \\ arXiv:1510.04672 replaced with revised version Thu, 25 Feb 2016 17:14:06 GMT (670kb) Title: Efficient Formation of Ultracold Molecules with Chirped Nanosecond Pulses Authors: J. L. Carini, S. Kallush, R. Kosloff, and P. L. Gould Categories: physics.atom-ph DOI: 10.1021/acs.jpca.5b10088 \\ ( http://arxiv.org/abs/1510.04672 , 670kb) ------------------------------------------------------------------------------ \\ arXiv:1510.07947 replaced with revised version Thu, 25 Feb 2016 07:40:22 GMT (1189kb) Title: Strong-field ionization inducing multi-electron-hole coherence probed by attosecond pulses Authors: Jing Zhao and Jianmin Yuan and Zengxiu Zhao Categories: physics.atom-ph Comments: 4 figures \\ ( http://arxiv.org/abs/1510.07947 , 1189kb) ------------------------------------------------------------------------------ \\ arXiv:1511.01507 (*cross-listing*) replaced with revised version Wed, 24 Feb 2016 23:52:26 GMT (356kb,D) Title: A Predictive Analytic Model for the Solar Modulation of Cosmic Rays Authors: Ilias Cholis, Dan Hooper and Tim Linden Categories: astro-ph.SR astro-ph.HE hep-ph physics.space-ph Comments: 15 pages, 7 figures and 2 tables, changes in v2: in agreement with PRD published version, small revisions in text, results and conclusions unchanged Report-no: FERMILAB-PUB-15-477-A \\ ( http://arxiv.org/abs/1511.01507 , 356kb) ------------------------------------------------------------------------------ \\ arXiv:1511.02739 (*cross-listing*) replaced with revised version Thu, 25 Feb 2016 18:39:33 GMT (2388kb) Title: Probing vacuum-induced coherence via magneto-optical rotation in molecular systems Authors: Pardeep Kumar, Bimalendu Deb, and Shubhrangshu Dasgupta Categories: quant-ph physics.optics \\ ( http://arxiv.org/abs/1511.02739 , 2388kb) ------------------------------------------------------------------------------ \\ arXiv:1512.03683 replaced with revised version Thu, 25 Feb 2016 01:41:52 GMT (367kb) Title: Rotational relaxation time as unifying time scale for polymer and fiber drag reduction Authors: A.M.P. Boelens and M. Muthukumar Categories: physics.flu-dyn \\ ( http://arxiv.org/abs/1512.03683 , 367kb) ------------------------------------------------------------------------------ \\ arXiv:1512.04511 (*cross-listing*) replaced with revised version Thu, 25 Feb 2016 17:43:30 GMT (6163kb,D) Title: The magnetic shear-current effect: generation of large-scale magnetic fields by the small-scale dynamo Authors: Jonathan Squire and Amitava Bhattacharjee Categories: astro-ph.HE astro-ph.SR physics.flu-dyn physics.plasm-ph \\ ( http://arxiv.org/abs/1512.04511 , 6163kb) ------------------------------------------------------------------------------ \\ arXiv:1512.05274 replaced with revised version Thu, 25 Feb 2016 10:24:21 GMT (376kb,D) Title: Griffiths effects of the susceptible-infected-susceptible epidemic model on random power-law networks Authors: Wesley F. C. Cota, Silvio C. Ferreira, G\'eza \'Odor Categories: physics.soc-ph cond-mat.dis-nn cond-mat.stat-mech Comments: 10 pages, 8 figures. Version accepted for publication in PRE \\ ( http://arxiv.org/abs/1512.05274 , 376kb) ------------------------------------------------------------------------------ \\ arXiv:1601.07916 replaced with revised version Thu, 25 Feb 2016 19:35:16 GMT (983kb,D) Title: Wicking through a confined micropillar array Authors: Baptiste Darbois Texier, Philippe Laurent, Serguei Stoukatch, St\'ephane Dorbolo Categories: physics.flu-dyn cond-mat.soft \\ ( http://arxiv.org/abs/1601.07916 , 983kb) ------------------------------------------------------------------------------ \\ arXiv:1602.06866 (*cross-listing*) replaced with revised version Thu, 25 Feb 2016 17:20:49 GMT (1731kb,D) Title: Forecasting the Flu: Designing Social Network Sensors for Epidemics Authors: Huijuan Shao, K.S.M. Tozammel Hossain, Hao Wu, Maleq Khan, Anil Vullikanti, B. Aditya Prakash, Madhav Marathe and Naren Ramakrishnan Categories: cs.SI physics.soc-ph Comments: The conference version of the paper is submitted for publication \\ ( http://arxiv.org/abs/1602.06866 , 1731kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07300 (*cross-listing*) replaced with revised version Thu, 25 Feb 2016 06:18:47 GMT (949kb,D) Title: When does inequality freeze an economy? Authors: Joao Pedro Jerico, Fran\c{c}ois P. Landes, Matteo Marsili, Isaac P\'erez Castillo and Valerio Volpati Categories: q-fin.EC physics.soc-ph \\ ( http://arxiv.org/abs/1602.07300 , 949kb) ------------------------------------------------------------------------------ \\ arXiv:1602.07529 replaced with revised version Thu, 25 Feb 2016 04:26:24 GMT (4kb) Title: A distribution of energies of a charged black hole Authors: Katsutaro Shimizu Categories: physics.gen-ph \\ ( http://arxiv.org/abs/1602.07529 , 4kb) %%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%--- For subscribe options to combined physics archives, e-mail To: physics@arxiv.org, Subject: subscribe ----------------------------------------------------------------------------- For help on viewing and making submissions, see http://arxiv.org/help/