Date: Tue, 29 Sep 15 00:32:30 GMT Subject: hep-lat daily 7 new + 7 crosses received by eprepget ------------------------------------------------------------------------------ ------------------------------------------------------------------------------ Send any comments regarding submissions directly to submitter. ------------------------------------------------------------------------------ Archives at http://arxiv.org/ To unsubscribe, e-mail To: hep-lat@arXiv.org, Subject: cancel ------------------------------------------------------------------------------ received by eprepget from Thu 24 Sep 15 20:00:00 GMT to Mon 28 Sep 15 20:00:00 GMT ------------------------------------------------------------------------------ \\ arXiv:1509.07874 Date: Fri, 25 Sep 2015 20:04:48 GMT (648kb,D) Title: Renormalization of the Polyakov loop with gradient flow Authors: P. Petreczky, H.-P. Schadler Categories: hep-lat Comments: 10 pages ReVTeX, 9 figures \\ We use the gradient flow for the renormalization of the Polyakov loop in various representations. Using 2+1 flavor QCD with highly improved staggered quarks (HISQ) and lattices with temporal extents of $N_\tau=6$, $8$, $10$ and $12$ we calculate the renormalized Polyakov loop in many representations including fundamental, sextet, adjoint, decuplet, 15-plet, 24-plet and 27-plet. This approach allows for the calculations of the renormalized Polyakov loops over a large temperature range from $T=116$ MeV up to $T=815$ MeV, with small errors not only for the Polyakov loop in fundamental representation, but also for the Polyakov loops in higher representations. We compare our results with standard renormalization schemes and discuss the Casimir scaling of the Polyakov loops. \\ ( http://arxiv.org/abs/1509.07874 , 648kb) ------------------------------------------------------------------------------ \\ arXiv:1509.07929 Date: Sat, 26 Sep 2015 00:50:11 GMT (69kb,D) Title: Perturbative results for two and three particle threshold energies in finite volume Authors: Maxwell T. Hansen and Stephen R. Sharpe Categories: hep-lat nucl-th Comments: 15 pages, 5 figures \\ We calculate the energy of the state closest to threshold for two and three identical, spinless particles confined to a cubic spatial volume with periodic boundary conditions and with zero total momentum in the finite-volume frame. The calculation is performed in relativistic quantum field theory with particles coupled via a $\lambda \phi^4$ interaction, and we work through order $\lambda^3$. The energy shifts begin at ${\cal O}(1/L^3)$, and we keep subleading terms proportional to $1/L^4$, $1/L^5$ and $1/L^6$. These terms allow a non-trivial check of the results obtained from quantization conditions that hold for arbitrary interactions, namely that of L\"uscher for two particles and our recently developed formalism for three particles. We also compare to previously obtained results based on non-relativistic quantum mechanics. \\ ( http://arxiv.org/abs/1509.07929 , 69kb) ------------------------------------------------------------------------------ \\ arXiv:1509.07959 Date: Sat, 26 Sep 2015 10:17:51 GMT (77kb,D) Title: Physical observables from boundary artifacts: scalar glueball in Yang-Mills theory Authors: Abhishek Chowdhury, A. Harindranath and Jyotirmoy Maiti Categories: hep-lat hep-ex hep-ph Comments: 12 pages, 7 figures \\ By relating the functional averages of the time slice energy density in simulations with Open (O) and Periodic (P) boundary conditions (BCs) respectively for $SU(3)$ lattice gauge theory, we show that the scalar glueball mass and the glueball to vacuum matrix element can be extracted very efficiently from the former. The results are compared with those extracted from the two point function of the time slice energy density (both PBC and OBC). The scaling properties of the mass and the matrix element are studied with the help of Wilson (gradient) flow. \\ ( http://arxiv.org/abs/1509.07959 , 77kb) ------------------------------------------------------------------------------ \\ arXiv:1509.08176 Date: Mon, 28 Sep 2015 02:22:46 GMT (1660kb,D) Title: Lefschetz thimble structure in one-dimensional lattice Thirring model at finite density Authors: H. Fujii, S. Kamata, Y. Kikukawa Categories: hep-lat Comments: 32 pages, 14 figures \\ We investigate Lefschetz thimble structure of the complexified path-integration in the one-dimensional lattice massive Thirring model with finite chemical potential. The lattice model is formulated with staggered fermions and a compact auxiliary vector boson (a link field), and the whole set of the critical points (the complex saddle points) are sorted out, where each critical point turns out to be in a one-to-one correspondence with a singular point of the effective action (or a zero point of the fermion determinant). For a subset of critical point solutions in the uniform-field subspace, we examine the upward and downward cycles and the Stokes phenomenon with varying the chemical potential, and we identify the intersection numbers to determine the thimbles contributing to the path-integration of the partition function. We show that the original integration path becomes equivalent to a single Lefschetz thimble at small and large chemical potentials, while in the crossover region multi thimbles must contribute to the path integration. Finally, reducing the model to a uniform field space, we study the relative importance of multiple thimble contributions and their behavior toward continuum and low-temperature limits quantitatively, and see how the rapid crossover behavior is recovered by adding the multi thimble contributions at low temperatures. Those findings will be useful for performing Monte-Carlo simulations on the Lefschetz thimbles. \\ ( http://arxiv.org/abs/1509.08176 , 1660kb) ------------------------------------------------------------------------------ \\ arXiv:1509.08226 Date: Mon, 28 Sep 2015 07:48:46 GMT (44kb,D) Title: Singlet baryons in the graded symmetry approach to partially quenched QCD Authors: J. M. M. Hall and D. B. Leinweber Categories: hep-lat Report-no: ADP-15-33/T935 \\ Progress in the calculation of the electromagnetic properties of baryon excitations in lattice QCD is presenting new challenges in the determination of sea-quark loop contributions to matrix elements. A reliable estimation of the sea-quark loop contributions presents a pressing issue in the accurate comparison of lattice QCD results with experiment. In this article, an extension of the graded symmetry approach to partially quenched QCD is presented, which builds on previous theory by explicitly including flavor-singlet baryons in its construction. The formalism takes into account the interactions among both octet and singlet baryons, octet mesons, and their ghost counterparts; the latter enables the isolation of the quark-flow disconnected sea-quark loop contributions. The introduction of the flavor-singlet states anticipates the application of the method to baryon excitations such as the lowest-lying odd-parity Lambda baryon, the Lambda(1405), which is considered in detail as a worked example. \\ ( http://arxiv.org/abs/1509.08226 , 44kb) ------------------------------------------------------------------------------ \\ arXiv:1509.08372 Date: Mon, 28 Sep 2015 15:55:19 GMT (570kb) Title: Lattice Calculation of the Connected Hadronic Light-by-Light Contribution to the Muon Anomalous Magnetic Moment Authors: Luchang Jin, Thomas Blum, Norman Christ, Masashi Hayakawa, Taku Izubuchi, Christoph Lehner Categories: hep-lat Comments: Twelfth Conference on the Intersections of Particle and Nuclear Physics. Vail Colorado at the Vail Marriott from May 19-24, 2015 \\ The anomalous magnetic moment of muon, $g-2$, is a very precisely measured quantity. However, the current measurement disagrees with standard model by about 3 standard deviations. Hadronic vacuum polarization and hadronic light by light are the two types of processes that contribute most to the theoretical uncertainty. I will describe how lattice methods are well-suited to provide a first-principle's result for the hadronic light by light contribution, the various numerical strategies that are presently being used to evaluate it, our current results and the important remaining challenges which must be overcome. \\ ( http://arxiv.org/abs/1509.08372 , 570kb) ------------------------------------------------------------------------------ \\ arXiv:1509.08391 Date: Mon, 28 Sep 2015 16:56:18 GMT (370kb,D) Title: An efficient algorithm for numerical computations of continuous densities of states Authors: Kurt Langfeld, Biagio Lucini, Roberto Pellegrini, Antonio Rago Categories: hep-lat Comments: 31 pages, 8 figures \\ In Wang-Landau type algorithms, Monte-Carlo updates are performed with respect to the density of states, which is iteratively refined during simulations. The partition function and thermodynamic observables are then obtained by standard integration. In this work, our recently introduced method in this class (the LLR approach) is analysed and further developed. Our approach is a histogram free method particularly suited for systems with continuous degrees of freedom giving rise to a continuum density of states, as it is commonly found in Lattice Gauge Theories and in some Statistical Mechanics systems. We show that the method possesses an exponential error suppression that allows us to estimate the density of states over several orders of magnitude with nearly-constant {\it relative} precision. We explain how ergodicity issues can be avoided and how expectation values of arbitrary observables can be obtained within this framework. We then demonstrate the method using Compact U(1) Lattice Gauge Theory. A thorough study of the algorithm parameter dependence of the results is performed and compared with the analytically expected behaviour. We obtain high precision values for the critical coupling for the phase transition and for the peak value of the specific heat for lattice sizes ranging from $8^4$ to $20^4$. Our results perfectly agree with the reference values reported in the literature, which covers lattice sizes up to $18^4$. Robust results for the $20^4$ volume are obtained for the first time. This latter investigation, which, due to strong metastabilities developed at the pseudo-critical coupling, so far has been out of reach even on supercomputers with importance sampling approaches, has been performed to high accuracy with modest computational resources. Other situations where the method is expected to be superior to importance sampling techniques are pointed out. \\ ( http://arxiv.org/abs/1509.08391 , 370kb) %-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%- ------------------------------------------------------------------------------ \\ arXiv:1509.07568 (*cross-listing*) Date: Thu, 24 Sep 2015 23:35:59 GMT (88kb,D) Title: Missing strange resonances in Lattice QCD Authors: Micha{\l} Marczenko Categories: nucl-th hep-lat Comments: 4 pages, 2 figures, prepared for the Strangeness in Quark Matter 2015 conference proceedings \\ Recent Lattice QCD (LQCD) studies suggest that there are missing resonances in the strange sector of the Hadron Resonance Gas (HRG) model. By adopting the continuous Hagedorn mass spectrum, we present how different medium compositions influence the HRG predictions of conserved charge fluctuations. It is shown that missing strange resonances may be partially accounted for by applying the Hagedorn mass spectrum extracted from experimentally established hadrons. On the other hand, the strange-baryonic spectra, extracted from LQCD results for fluctuations, are found to be consistent with the unconfirmed states in the Particle Data Group (PDG) database, whilst the strange-mesonic spectrum points towards yet undiscovered states in the intermediate mass region. \\ ( http://arxiv.org/abs/1509.07568 , 88kb) ------------------------------------------------------------------------------ \\ arXiv:1509.07665 (*cross-listing*) Date: Fri, 25 Sep 2015 10:30:54 GMT (90kb) Title: What is dimensional reduction really telling us? Authors: Daniel Coumbe Categories: hep-th gr-qc hep-lat Comments: 6 pages, 2 figures. Contribution to the proceedings of MG14, Rome July 2015 \\ Numerous approaches to quantum gravity report a reduction in the number of spacetime dimensions at the Planck scale. However, accepting the reality of dimensional reduction also means accepting its consequences, including a variable speed of light. We provide numerical evidence for a variable speed of light in the causal dynamical triangulation (CDT) approach to quantum gravity, showing that it closely matches the superluminality implied by dimensional reduction. We argue that reconciling the appearance of dimensional reduction with a constant speed of light may require modifying our understanding of time, an idea originally proposed in Ref. 1. \\ ( http://arxiv.org/abs/1509.07665 , 90kb) ------------------------------------------------------------------------------ \\ arXiv:1509.07682 (*cross-listing*) Date: Fri, 25 Sep 2015 11:24:36 GMT (272kb) Title: Undersaturation of quarks at early stages of relativistic nuclear collisions: the hot glue initial scenario and its observable signatures Authors: H. Stoecker, M. Beitel, T.S. Bir\'o, L.P. Csernai, K. Gallmeister, M.I. Gorenstein, C. Greiner, I.N. Mishustin, M. Panero, S. Raha, L.M. Satarov, S. Schramm, F. Senzel, B. Sinha, J. Steinheimer, J. Struckmeier, V. Vovchenko, Z. Xu, K. Zhou, P. Zhuang Categories: hep-ph hep-ex hep-lat nucl-ex nucl-th Comments: 5 pages, 7 figures, proceeding for STARS2015 symposium \\ The early stage of high multiplicity nuclear collisions is represented by a nearly quarkless, hot, deconfined pure gluon plasma. These new scenario should be characterized by a suppression of high $p_T$ photons and dileptons as well as by reduced baryon to meson ratios. We present the numerical results for central Pb+Pb collisions at the LHC energies by using the ideal Bjorken hydrodynamics with time-dependent quark fugacity. It is shown that about 25\% of final total entropy is generated during the hydrodynamic evolution of chemically undersaturated quark-gluon plasma. \\ ( http://arxiv.org/abs/1509.07682 , 272kb) ------------------------------------------------------------------------------ \\ arXiv:1509.07697 (*cross-listing*) Date: Fri, 25 Sep 2015 12:39:02 GMT (645kb,D) Title: Matching effective few-nucleon theories to QCD Authors: Johannes Kirscher Categories: nucl-th hep-lat Comments: Review article commissioned for IJMPe, 22 pages \\ The emergence of complex macroscopic phenomena from a small set of parameters and microscopic concepts demonstrates the power and beauty of physical theories. The wealth of data and peculiarities found in nuclei and the small number of parameters and symmetries of quantum chromodynamics are prominent examples for this conjecture. Decade-long research on computational physics and on effective field theories facilitate the assessment of the presumption that quark masses and strong and electromagnetic coupling constants suffice to parameterize the nuclear chart. By presenting the current status of that enterprise, this article touches the methodology of predicting nuclei by simulating the constituting quarks and the development of more appropriate representations of the fundamental theory. While the systems analyzed computationally so far are in close resemblance to those which intrigued experimentalists a century ago, they also test the theoretical understanding which was unavailable to guide the nuclear pioneers but developed since then. This understanding is shown to be deficient in terms of correlations amongst nuclear observables and their sensitivity to fundamental parameters. By reviewing the transition from one effective field theory to another, from QCD to pionful chiral theories to pionless and eventually to cluster theories, we identify some of those deficiencies and conceptual problems awaiting a solution before QCD can be identified as the high-energy theory from which the nuclear landscape emerges. \\ ( http://arxiv.org/abs/1509.07697 , 645kb) ------------------------------------------------------------------------------ \\ arXiv:1509.08125 (*cross-listing*) Date: Sun, 27 Sep 2015 19:12:35 GMT (105kb) Title: Low-energy constants from ALEPH hadronic tau decay data Authors: Diogo Boito, Anthony Francis, Maarten Golterman, Renwick Hudspith, Randy Lewis, Kim Maltman, Santiago Peris Categories: hep-ph hep-lat Comments: 6 pages, contribution to the proceedings of Chiral Dynamics 2015 \\ We determined the NLO chiral low-energy constant $L_{10}$, and various combinations of NNLO chiral low-energy constants employing recently revised ALEPH results for the non-strange vector (V) and axial-vector (A) hadronic tau decay distributions and recently updated RBC/UKQCD lattice data for the non-strange V-A two-point function. In this talk, we explain the ingredients of this determination. Our errors are at or below the level expected for contributions of yet higher order in the chiral expansion, suggesting that our results exhaust the possibilities of what can be meaningfully achieved in an NNLO analysis. \\ ( http://arxiv.org/abs/1509.08125 , 105kb) ------------------------------------------------------------------------------ \\ arXiv:1509.08290 (*cross-listing*) Date: Mon, 28 Sep 2015 12:13:32 GMT (183kb,D) Title: Clustering in nuclei from ab initio nuclear lattice simulations Authors: Ulf-G. Mei{\ss}ner Categories: nucl-th hep-lat hep-ph nucl-ex Comments: Contibution to "Chiral Dynamics 2015'', Pisa, Italy, June 29 to July 3, 2015 \\ Nuclear Lattice Effective Field Theory is a new many-body approach that is firmly rooted in the symmetries of QCD. In particular, it allows for truly ab initio calculations of nuclear structure and reactions. In this talk, I focus on the emergence of alpha-clustering in nuclei based on this approach. I also discuss various recent achievements, the deficiencies of the chiral forces used at present and the prospects to improve upon these and the calculations of nuclear properties and dynamics. \\ ( http://arxiv.org/abs/1509.08290 , 183kb) ------------------------------------------------------------------------------ \\ arXiv:1509.08436 (*cross-listing*) Date: Mon, 28 Sep 2015 19:22:03 GMT (62kb) Title: A covariant model for the negative parity resonances of the nucleon Authors: G. Ramalho Categories: hep-ph hep-ex hep-lat nucl-ex nucl-th Comments: Proceedings of the workshop "XIII International Workshop on Hadron Physics", 22-27 March 2015, Hotel do Bosque, Angra dos Reis - RJ, Brazil. 8 pages, 7 figures \\ We present a model for the $\gamma^\ast N \to N^\ast$ helicity amplitudes, where $N$ is the nucleon and $N^\ast$ is a negative parity nucleon excitation, member of the $SU(6)$-multiplet $[70,1^-]$. The model combines the results from the single quark transition model for the helicity amplitudes with the results of the covariant spectator quark model for the $\gamma^\ast N \to N^\ast(1535)$ and $\gamma^\ast N \to N^\ast(1520)$ transitions. With the knowledge of the amplitudes $A_{1/2}$ and $A_{3/2}$ for those transitions we calculate three independent coefficients defined by the single quark transition model and make predictions for the helicity amplitudes associated with the $\gamma^\ast N \to N^\ast(1650)$, $\gamma^\ast N \to N^\ast(1700)$, $\gamma^\ast N \to \Delta(1620)$, and $\gamma^\ast N \to \Delta(1700)$ transitions. In order to facilitate the comparison with future experimental data at high $Q^2$, we provide also simple parametrizations for the amplitudes, compatible with the expected falloff at high $Q^2$. \\ ( http://arxiv.org/abs/1509.08436 , 62kb) %%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%% ------------------------------------------------------------------------------ \\ arXiv:1402.0389 replaced with revised version Fri, 25 Sep 2015 11:26:18 GMT (135kb,D) Title: A non-perturbative mechanism for elementary particle mass generation Authors: R. Frezzotti and G.C. Rossi Categories: hep-lat hep-th Comments: Added more information in Fig 1. Added Fig. 10. Added an extra Appendix. Restructured a few sentences according to referee suggestions. Corrected a few misprints. All results unchanged. Now 50 pages and 10 Figures Journal-ref: Phys. Rev. D 92, 054505 (2015) DOI: 10.1103/PhysRevD.92.054505 \\ ( http://arxiv.org/abs/1402.0389 , 135kb) ------------------------------------------------------------------------------ \\ arXiv:1504.04463 (*cross-listing*) replaced with revised version Fri, 25 Sep 2015 10:18:43 GMT (163kb) Title: Determination of $U(1)_{\rm A}$ restoration from pion and $a_0$-meson screening masses: Toward the chiral regime Authors: Masahiro Ishii, Koji Yonemura, Junichi Takahashi, Hiroaki Kouno, Masanobu Yahiro Categories: hep-ph hep-lat nucl-th Comments: 10 pages, 12 figures \\ ( http://arxiv.org/abs/1504.04463 , 163kb) ------------------------------------------------------------------------------ \\ arXiv:1507.03858 replaced with revised version Fri, 25 Sep 2015 09:57:17 GMT (760kb,D) Title: Thimble regularization at work: from toy models to chiral random matrix theories Authors: Francesco Di Renzo and Giovanni Eruzzi Categories: hep-lat hep-th Comments: 33 pages, 8 figures. Some extra references have been added and subsection 3.1 has been substantially expanded. Some extra comments on numerics have also been added in subsection 4.4. Appendix A and appendix B.1 now features some more details \\ ( http://arxiv.org/abs/1507.03858 , 760kb) ------------------------------------------------------------------------------ \\ arXiv:1508.01042 replaced with revised version Fri, 25 Sep 2015 19:58:53 GMT (1227kb,D) Title: Colorful plane vortices and Chiral Symmetry Breaking in $SU(2)$ Lattice Gauge Theory Authors: Seyed Mohsen Hosseini Nejad, Manfried Faber and Roman H\"ollwieser Categories: hep-lat Comments: 15 pages, 14 figures \\ ( http://arxiv.org/abs/1508.01042 , 1227kb) ------------------------------------------------------------------------------ \\ arXiv:1505.02218 replaced with revised version Fri, 25 Sep 2015 22:07:13 GMT (293kb,D) Title: Impact of electromagnetism on phase structure for Wilson and twisted-mass fermions including isospin breaking Authors: Derek P. Horkel and Stephen R. Sharpe Categories: hep-lat Comments: 15 pages, 5 figures. v2: Minor stylistic changes and references updated. Published version \\ ( http://arxiv.org/abs/1505.02218 , 293kb) ------------------------------------------------------------------------------ \\ arXiv:1506.08638 replaced with revised version Sat, 26 Sep 2015 12:06:27 GMT (122kb,D) Title: Hadronic vacuum polarization and muon g-2 from magnetic susceptibilities on the lattice Authors: Gunnar Bali, Gergely Endrodi Categories: hep-lat hep-ph Comments: 15 pages, 9 figures, v2: minor changes in the text, version published in PRD \\ ( http://arxiv.org/abs/1506.08638 , 122kb) ------------------------------------------------------------------------------ \\ arXiv:1507.03717 (*cross-listing*) replaced with revised version Sun, 27 Sep 2015 06:40:19 GMT (84kb,D) Title: Towards exotic hidden-charm pentaquarks in QCD Authors: Hua-Xing Chen, Wei Chen, Xiang Liu, T. G. Steele and Shi-Lin Zhu Categories: hep-ph hep-ex hep-lat nucl-th Comments: 5 pages and 1 figure. More discussions and references added. Accepted by Phys. Rev. Lett (in press) \\ ( http://arxiv.org/abs/1507.03717 , 84kb) ------------------------------------------------------------------------------ \\ arXiv:1508.05485 (*cross-listing*) replaced with revised version Mon, 28 Sep 2015 02:59:35 GMT (15kb) Title: The $Z_2$ Index of Disordered Topological Insulators with Time Reversal Symmetry Authors: Hosho Katsura and Tohru Koma Categories: math-ph cond-mat.dis-nn cond-mat.mes-hall hep-lat hep-th math.MP Comments: 17 pages, no figure, v2: minor corrections, Appendix C and references added \\ ( http://arxiv.org/abs/1508.05485 , 15kb) ------------------------------------------------------------------------------ \\ arXiv:1509.04616 replaced with revised version Mon, 28 Sep 2015 00:32:41 GMT (331kb,D) Title: Stochastic sandwich method with low mode substitution for nucleon isovector matrix elements Authors: Yi-Bo Yang, Andrei Alexandru, Terrence Draper, Ming Gong, and Keh-Fei Liu Categories: hep-lat hep-ph Comments: 14 pages, 13 figures, references updated \\ ( http://arxiv.org/abs/1509.04616 , 331kb) %%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%--- 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/