Date: Wed, 29 Nov 17 01:19:55 GMT Subject: gr-qc daily 13 new + 12 crosses received by eprepget ------------------------------------------------------------------------------ ------------------------------------------------------------------------------ Send any comments regarding submissions directly to submitter. ------------------------------------------------------------------------------ Archives at http://arxiv.org/ To unsubscribe, e-mail To: gr-qc@arXiv.org, Subject: cancel ------------------------------------------------------------------------------ received by eprepget from Mon 27 Nov 17 19:00:00 GMT to Tue 28 Nov 17 19:00:00 GMT ------------------------------------------------------------------------------ \\ arXiv:1711.09891 Date: Mon, 27 Nov 2017 10:33:38 GMT (74kb,D) Title: Scalar-metric quantum cosmology with Chaplygin gas and perfect fluid Authors: Saumya Ghosh, Sunandan Gangopadhyay, Prasanta K. Panigrahi Categories: gr-qc hep-th Comments: 8 pages LateX \\ In this paper we consider the flat FRW cosmology with a scalar field coupled with the metric along with generalized Chaplygin gas and perfect fluid comprising the matter sector. We use the Schutz's formalism to deal with the generalized Chaplygin gas sector. The full theory is then quantized canonically using the Wheeler-DeWitt Hamiltonian formalism. We then solve the WD equation with appropriate boundary conditions. Then by defining a proper completeness relation for the self-adjointness of the WD equation we arrive at the wave packet for the universe. It is observed that the peak in the probability density gets affected due to both fluids in the matter sector, namely, the Chaplygin gas and perfect fluid. \\ ( https://arxiv.org/abs/1711.09891 , 74kb) ------------------------------------------------------------------------------ \\ arXiv:1711.09893 Date: Mon, 27 Nov 2017 15:21:23 GMT (66kb) Title: A general theory of linear cosmological perturbations: stability conditions, the quasistatic limit and dynamics Authors: Macarena Lagos, Emilio Bellini, Johannes Noller, Pedro G. Ferreira, Tessa Baker Categories: gr-qc hep-th \\ We analyse cosmological perturbations around a homogeneous and isotropic background for scalar-tensor, vector-tensor and bimetric theories of gravity. Building on previous results, we propose a unified view of the effective parameters of all these theories. Based on this structure, we explore the viable space of parameters for each family of models by imposing the absence of ghosts and gradient instabilities. We then focus on the quasistatic regime and confirm that all these theories can be approximated by the phenomenological two-parameter model described by an effective Newton's constant and the gravitational slip. Within the quasistatic regime we pinpoint signatures which can distinguish between the broad classes of models (scalar-tensor, vector-tensor or bimetric). Finally, we present the equations of motion for our unified approach in such a way that they can be implemented in Einstein-Boltzmann solvers. \\ ( https://arxiv.org/abs/1711.09893 , 66kb) ------------------------------------------------------------------------------ \\ arXiv:1711.09919 Date: Mon, 27 Nov 2017 19:00:09 GMT (1477kb,D) Title: Denoising Gravitational Waves using Deep Learning with Recurrent Denoising Autoencoders Authors: Hongyu Shen, Daniel George, E. A. Huerta, Zhizhen Zhao Categories: gr-qc astro-ph.HE astro-ph.IM cs.LG cs.NE Comments: 5 pages, 2 figures \\ Gravitational wave astronomy is a rapidly growing field of modern astrophysics, with observations being made frequently by the LIGO detectors. Gravitational wave signals are often extremely weak and the data from the detectors, such as LIGO, is contaminated with non-Gaussian and non-stationary noise, often containing transient disturbances which can obscure real signals. Traditional denoising methods, such as principal component analysis and dictionary learning, are not optimal for dealing with this non-Gaussian noise, especially for low signal-to-noise ratio gravitational wave signals. Furthermore, these methods are computationally expensive on large datasets. To overcome these issues, we apply state-of-the-art signal processing techniques, based on recent groundbreaking advancements in deep learning, to denoise gravitational wave signals embedded either in Gaussian noise or in real LIGO noise. We introduce SMTDAE, a Staired Multi-Timestep Denoising Autoencoder, based on sequence-to-sequence bi-directional Long-Short-Term-Memory recurrent neural networks. We demonstrate the advantages of using our unsupervised deep learning approach and show that, after training only using simulated Gaussian noise, SMTDAE achieves superior recovery performance for gravitational wave signals embedded in real non-Gaussian LIGO noise. \\ ( https://arxiv.org/abs/1711.09919 , 1477kb) ------------------------------------------------------------------------------ \\ arXiv:1711.09922 Date: Mon, 27 Nov 2017 19:00:15 GMT (76kb) Title: Eternal and Evanescent Black Holes: It's All Done With Mirrors Authors: Michael R.R. Good, Eric V. Linder Categories: gr-qc Comments: 13 pages, 11 figures \\ The analogy between black hole radiation and accelerating mirror radiation (the dynamical Casimir effect) is particularly strong for mirror trajectories giving rise to a constant thermal flux of particles. We present new ways to achieve such thermal plateaus, and customize their finite, semi-infinite, and eternal presence, corresponding to forming/collapsing, complete-evaporation/remnants, and eternal black holes. We find simple expressions for the energy flux in terms of the mirror rapidity as a function of proper time and null time. \\ ( https://arxiv.org/abs/1711.09922 , 76kb) ------------------------------------------------------------------------------ \\ arXiv:1711.09930 Date: Mon, 27 Nov 2017 19:04:54 GMT (18kb) Title: Teleparallel theories of gravity as analogue of non-linear electrodynamics Authors: Manuel Hohmann, Laur J\"arv, Martin Kr\v{s}\v{s}\'ak, Christian Pfeifer Categories: gr-qc hep-th math-ph math.MP Comments: 12 pages, no figures \\ The teleparallel formulation of gravity theories reveals close structural analogies to electrodynamics, which are more hidden in their usual formulation in terms of the curvature of spacetime. We show how every locally Lorentz invariant teleparallel theory of gravity with second order field equations can be understood as built from a gravitational field strength and excitation tensor which are related to each other by a constitutive relation, analogous to the axiomatic construction of theories of electrodynamics. We demonstrate how the previously studied models of $f(\mathbb{T})$ and $f(T_\text{ax},T_\text{ten},T_\text{vec})$ gravity as well as teleparallel dark energy can be formulated in this language. The advantage of this approach to gravity is that the field equations for different models all take the same compact form and general results can be obtained. An important new such result we find is a constraint which relates the field equations of the tetrad and the spin connection. \\ ( https://arxiv.org/abs/1711.09930 , 18kb) ------------------------------------------------------------------------------ \\ arXiv:1711.09963 Date: Mon, 27 Nov 2017 20:13:16 GMT (17kb) Title: Systolic aspects of black hole entropy Authors: Nikolaos Kalogeropoulos Categories: gr-qc cond-mat.stat-mech hep-th math-ph math.MP Comments: 19 pages. No figures. LaTeX2e \\ We attempt to provide a mesoscopic treatment of the origin of black hole entropy in (3+1)-dimensional spacetimes. We ascribe this entropy to the non-trivial topology of the space-like sections $\Sigma$ of the horizon. This is not forbidden by topological censorship, since all the known energy inequalities needed to prove the spherical topology of $\Sigma$ are violated in quantum theory. We choose the systoles of $\Sigma$ to encode its complexity, which gives rise to the black hole entropy. We present hand-waving reasons why the entropy of the black hole can be considered as a function of the volume entropy of $\Sigma$. We focus on the limiting case of $\Sigma$ having a large genus. \\ ( https://arxiv.org/abs/1711.09963 , 17kb) ------------------------------------------------------------------------------ \\ arXiv:1711.10054 Date: Tue, 28 Nov 2017 00:04:24 GMT (7380kb,D) Title: The Smallest Shape Spaces. I. Shape Theory Posed, with Example of 3 Points on the Line Authors: Edward Anderson Categories: gr-qc Comments: 82 pages with 50 figures \\ This series of papers concerns shapes in the sense of constellations of points with various automorphisms quotiented out: the continuous translations, rotations and dilations, and also the discrete mirror image identification and labelling indistinguishability of the points. We consider in particular the corresponding configuration spaces, which include shape spaces and scale-and-shape spaces. This is a substantial model arena for developing concepts of Background Independence, with many analogies to General Relativity; it also has many applications in each of Dynamics and Statistics, and more. We also explain the necessity of working by the shape theoretic Aufbau Principle: only considering larger particle number $N$, spatial dimension $d$ and continuous group of automorphisms $G$ when all the relatively smaller cases have been considered. We show that topological shape spaces are graphs, which then provides useful underpinning structure for topological features of the more usually considered space of metric shapes. We give a conceptual analysis of clustering and uniformness aspects of inhomogeneous Background Independence. We also consider the fate of shape spaces' (similar) Killing vectors upon performing the mirror image and particle indistinguishability quotientings. This is crucial for dynamical and quantization considerations. For now, in Paper I, we illustrate all these topological, combinatorial, differential-geometric and inhomogeneity innovations with the example of 3 points in 1-d. Papers II, III and IV then extend the repertoire of examples to 4 points in 1-$d$, triangles (3 points in 2- and 3-$d$) and quadrilaterals (4 points in 2-$d$) respectively. The quadrilateral is a minimal requirement prior to most implementations of the third `increase $G$ generators' part of the Aufbau Principle. \\ ( https://arxiv.org/abs/1711.10054 , 7380kb) ------------------------------------------------------------------------------ \\ arXiv:1711.10073 Date: Tue, 28 Nov 2017 01:04:29 GMT (8508kb,D) Title: The Smallest Shape Spaces. II. 4 Points in 1-d Suffices to have a Complex Background-Independent Theory of Inhomogeneity Authors: Edward Anderson Categories: gr-qc Comments: 43 pages with 36 figures \\ The program of understanding Shape Theory layer by layer topologically and geometrically -- proposed in Paper I -- is now addressed for 4 points in 1-$d$. Topological shape space graphs are far more complex here, whereas metric shape spaces are (pieces of) spheres admitting an intricate shape-theoretically significant tessellation. Metric shapes covers a far wider range of notions of inhomogeneity: collisions, symmetric states, mergers and uniform states are all distinctly realized in this model. We furthermore provide quantifiers for the extent to which various ways which configurations maximally and minimally realize these. Some of the uniform states additionally form cusps and higher catastrophes in the indistinguishable-particle and Leibniz shape spaces. We also provide shape-theoretically significant notions of centre for the indistinguishable-particle and Leibniz shape spaces. 4 points in 1-$d$ constitutes a useful and already highly nontrivial model of inhomogeneity and of uniformity (both topics of cosmological interest) and also of background independence (of interest in the foundations of physics and in quantum gravity). We finally give the automorphism groups of the topological shape space graphs and the metric shape space (pieces of) manifolds, which is a crucial preliminary toward quantizing the indistinguishable-particle and Leibniz versions of the model. \\ ( https://arxiv.org/abs/1711.10073 , 8508kb) ------------------------------------------------------------------------------ \\ arXiv:1711.10080 Date: Tue, 28 Nov 2017 01:44:15 GMT (87kb,D) Title: Noether symmetry approach in the cosmological alpha-attractors Authors: Narakorn Kaewkhao (Prince Songkla U.), Thanyagamon Kanesom (Prince Songkla U.) and Phongpichit Channuie (Walailak U.) Categories: gr-qc hep-ph hep-th Comments: v1: 8 pages, 5 figures \\ In cosmological framework, Noether symmetry technique has revealed a useful tool in order to examine exact solutions. In this work, we analyse the dynamics of the field in the cosmological alpha-attractors using the Noether sysmetry technique by focusing on the single field scenario in the Einstein-frame form. We show that with a Noether symmetry the coresponding dynamical system can be completely integrated and the potential exhibited by the symmetry can be exactly obtained. Interestingly, the solutions of the system can possibly describe the transition from a decelerated to an accelerated expansion of the universe dictated from the scale factor. With the proper choice of parameters, the behavior of the scale factor shows the time-dependence with positively rational exponents at very early stage. Surprisingly, for all cases it has an exponential (de Sitter) behavior at the present epoch. Moreover, we discover that the Hubble parameters strongly depends on the initial values of parameters exhibited by the Noether symmetry. It is also constant in the present epoch in all cases. However, by properly choosing the initial values of the parameters, it can retardedly evolve before its values become a constant at the present epoch. \\ ( https://arxiv.org/abs/1711.10080 , 87kb) ------------------------------------------------------------------------------ \\ arXiv:1711.10115 Date: Tue, 28 Nov 2017 04:20:23 GMT (9166kb,D) Title: The Smallest Shape Spaces. III. Triangles in 2- and 3-d Authors: Edward Anderson Categories: gr-qc Comments: 64 pages and 50 figures \\ We apply Paper I's program of layer by layer study of understanding Shape Theory, now for triangles in 2-$d$. These are the smallest models with relative angle information as well as ratio information. We provide further study of shape sphere Kendall's spherical blackboard Leibniz space. We assess clustering and uniformity criteria, now making use of relative angle criteria as well. We also locate the right-angled triangles within the triangleland shape sphere and Leibniz space. This gives an answer to the well-known conundrum of what is the probability that a triangle is obtuse, in fact a well-known answer -- 3/4 -- but now obtained in a different way: as a very simple corollary of the differential geometry of shape space. We also give a general bundle section interpretation of Kendall's spherical blackboard, and furthermore attribute a new type of monopole to it. This work is based on Hopf mathematics and variants; this moreover places regularity -- the boundary between tall and flat triangles -- on the same footing as isoscelesness and collinearity. We end with two comparisons, firstly between triangles in 2-$d$ and Paper II's 4 points on the line. This illustrates many of the ways in which increasing dimension or point number by one makes a substantial difference. Secondly, we compare triangles in 2-$d$ and in 3-$d$, the latter being the smallest model with the subsequently crucial shape space feature of being stratified. We expect stratified manifold--sheaf pairs -- sheaves adding useful local and global structure to general bundles -- to lie at the heart of generic shape models. \\ ( https://arxiv.org/abs/1711.10115 , 9166kb) ------------------------------------------------------------------------------ \\ arXiv:1711.10256 Date: Tue, 28 Nov 2017 12:40:40 GMT (686kb,D) Title: Astrophysical Black Holes: A Compact Pedagogical Review Authors: Cosimo Bambi Categories: gr-qc astro-ph.HE Comments: 14 pages, 7 figures \\ Black holes are among the most extreme objects that can be found in the Universe and an ideal laboratory for testing fundamental physics. This article will briefly review the basic properties of black holes as expected from general relativity, the main astronomical observations, and the leading astrophysical techniques to probe the strong gravity region of these objects. It is mainly intended to provide a compact introductory overview on astrophysical black holes to new students entering this research field, as well as to senior researchers working in general relativity and alternative theories of gravity and wishing to quickly learn the state of the art of astronomical observations of black holes. \\ ( https://arxiv.org/abs/1711.10256 , 686kb) ------------------------------------------------------------------------------ \\ arXiv:1711.10278 Date: Tue, 28 Nov 2017 13:23:49 GMT (11kb) Title: Uncertainty principle for a quantum gravitational system Authors: V. E. Kuzmichev, V. V. Kuzmichev (Bogolyubov Institute for Theoretical Physics) Categories: gr-qc astro-ph.CO hep-th Comments: 11 pages \\ The new uncertainty relation is derived in the context of the canonical quantum theory with gravity for the case of the maximally symmetric space. This relation establishes a connection between fluctuations of the quantities which determine the intrinsic and extrinsic curvatures of the spacelike hypersurface in spacetime and introduces the new uncertainty principle for quantum gravitational systems. All known modifications of the uncertainty principle deduced previously from different approaches in the theory of gravity and string theory are obtained as particular cases of the proposed general expression. The generalized time-energy uncertainty relation, which takes into account gravity, is proposed. \\ ( https://arxiv.org/abs/1711.10278 , 11kb) ------------------------------------------------------------------------------ \\ arXiv:1711.10333 Date: Tue, 28 Nov 2017 15:14:26 GMT (26kb) Title: Canonical transformation path to gauge theories of gravity II --- Spacetime coupling of massive spin particle fields Authors: J. Struckmeier, P. Liebrich, J. Muench, M. Hanauske, J. Kirsch, D. Vasak, L. Satarov, H. Stoecker Categories: gr-qc hep-th nucl-th Comments: 12 pages \\ The generic form of spacetime dynamics as a gauge theory has recently been derived, based on only the action principle and on the general principle of relativity. In the present paper, the physical consequences are discussed. The gauge coupling terms obtained imply that Einstein's theory holds only for structureless (spin zero) particles, and aggregations of them. For massive particles with spin, however, spacetime dynamics is to be described by an additional, Poisson-type equation describing the interaction of the particle's spin with the torsion of spacetime. This equation shows that torsion propagates with gravitational waves. Spin carrying matter is thus shown to couple with the torsion of spacetime. The proper source term for the spacetime dynamics is given by the canonical energy-momentum tensor---which embraces also the energy density furnished by microscopic internal spin. This changes the model of compact astrophysical objects and of relativistic collapse dynamics, with significant impact on the description of binary neutron star mergers and pulsar dynamics. The final generally covariant Hamiltonian must contain a term quadratic in the conjugate momenta of the gauge fields in order to yield a closed system of field equations---in analogy to all other Hamiltonian descriptions of field theories. The fact that the canonical gauge theory of gravity derived here requires that both, quadratic curvature tensors and canonical energy momentum tensors, enter the field equation for the spacetime dynamics leads to a qualitatively new framework for general relativity---and to a new understanding of Friedman cosmology and the cosmological constant problem. \\ ( https://arxiv.org/abs/1711.10333 , 26kb) %-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%- ------------------------------------------------------------------------------ \\ arXiv:1711.08835 (*cross-listing*) Date: Thu, 23 Nov 2017 22:17:04 GMT (230kb,D) Title: AdS/CFT far from equilibrium in a Vaidya setup Authors: Michael Florian Wondrak, Matthias Kaminski, Piero Nicolini, Marcus Bleicher Categories: hep-th gr-qc Comments: 6 pages, 2 figures. Paper submitted to the Proceedings of the 3rd Karl Schwarzschild Meeting on Gravitational Physics and the Gauge/Gravity Correspondence, Frankfurt am Main, 24-28 July 2017 \\ In this paper we apply the AdS/CFT correspondence to study a strongly coupled plasma far from equilibrium with a strong emphasis on the shear behavior. The plasma serves as a model for an electrically charged quark-gluon plasma. On the gravitational side, we use an ingoing Vaidya black brane spacetime. The highest rate of mass infall is confined to a short time interval. \\ ( https://arxiv.org/abs/1711.08835 , 230kb) ------------------------------------------------------------------------------ \\ arXiv:1711.09915 (*cross-listing*) Date: Mon, 27 Nov 2017 19:00:06 GMT (126kb,D) Title: Primordial black holes from fifth forces Authors: Luca Amendola, Javier Rubio, Christof Wetterich Categories: astro-ph.CO gr-qc hep-th Comments: 5 pages, 1 figure \\ Primordial black holes can be produced by a long range attractive fifth force stronger than gravity, mediated by a light scalar field interacting with non-relativistic "heavy" particles. As soon as the energy fraction of heavy particles reaches a threshold, the fluctuations rapidly grow non-linear. The overdensities collapse into black holes or similar screened objects, without the need of any particular feature in the spectrum of primordial density fluctuations generated during inflation. We discuss if such primordial black holes can constitute the total dark matter component in the Universe. \\ ( https://arxiv.org/abs/1711.09915 , 126kb) ------------------------------------------------------------------------------ \\ arXiv:1711.09941 (*cross-listing*) Date: Mon, 27 Nov 2017 19:27:16 GMT (47kb,D) Title: Ryu-Takayanagi Formula for Symmetric Random Tensor Networks Authors: Goffredo Chirco, Daniele Oriti, Mingyi Zhang Categories: hep-th gr-qc math-ph math.MP quant-ph Comments: 10 pages, 4 figures \\ We consider the special case of Random Tensor Networks (RTN) endowed with gauge symmetry constraints on each tensor. We compute the R\`enyi entropy for such states and recover the Ryu-Takayanagi (RT) formula in the large bond regime. The result provides first of all an interesting new extension of the existing derivations of the RT formula for RTNs. Moreover, this extension of the RTN formalism brings it in direct relation with (tensorial) group field theories (and spin networks), and thus provides new tools for realizing the tensor network/geometry duality in the context of background independent quantum gravity, and for importing quantum gravity tools in tensor network research. \\ ( https://arxiv.org/abs/1711.09941 , 47kb) ------------------------------------------------------------------------------ \\ arXiv:1711.09968 (*cross-listing*) Date: Mon, 27 Nov 2017 20:21:48 GMT (65kb) Title: Electromagnetic Duality and the Electric Memory Effect Authors: Yuta Hamada, Min-Seok Seo, Gary Shiu Categories: hep-th gr-qc hep-ph Comments: 16 pages, 1 figure \\ We study large gauge transformations for soft photons in quantum electrodynamics which, together with the helicity operator, form an ISO(2) algebra. We show that the two non-compact generators of the ISO(2) algebra correspond respectively to the residual gauge symmetry and its electromagnetic dual gauge symmetry that emerge at null infinity. The former is helicity universal (electric in nature) while the latter is helicity distinguishing (magnetic in nature). Thus, the conventional large gauge transformation is electric in nature, and is naturally associated with a scalar potential. We suggest that the electric Aharonov-Bohm effect is a direct measure for the electromagnetic memory arising from large gauge transformations. \\ ( https://arxiv.org/abs/1711.09968 , 65kb) ------------------------------------------------------------------------------ \\ arXiv:1711.09986 (*cross-listing*) Date: Mon, 27 Nov 2017 20:48:55 GMT (1068kb,D) Title: Effective inertial frame in an atom interferometric test of the equivalence principle Authors: Chris Overstreet, Peter Asenbaum, Tim Kovachy, Remy Notermans, Jason M. Hogan, Mark A. Kasevich Categories: physics.atom-ph gr-qc quant-ph Comments: 5 pages, 4 figures \\ In an ideal test of the equivalence principle, the test masses fall in a common inertial frame. A real experiment is affected by gravity gradients, which introduce systematic errors by coupling to initial kinematic differences between the test masses. We demonstrate a method that reduces the sensitivity of a dual-species atom interferometer to initial kinematics by using a frequency shift of the mirror pulse to create an effective inertial frame for both atomic species. This suppresses the gravity-gradient-induced dependence of the differential phase on initial kinematic differences by a factor of 100 and enables a precise measurement of these differences. We realize a relative precision of $\Delta g / g \approx 6 \times 10^{-11}$ per shot, which improves on the best previous result for a dual-species atom interferometer by more than three orders of magnitude. By suppressing gravity gradient systematic errors to below one part in $10^{13}$, these results pave the way for an atomic test of the equivalence principle at an accuracy comparable with state-of-the-art classical tests. \\ ( https://arxiv.org/abs/1711.09986 , 1068kb) ------------------------------------------------------------------------------ \\ arXiv:1711.09989 (*cross-listing*) Date: Mon, 27 Nov 2017 20:53:04 GMT (504kb,D) Title: Eccentric Black Hole Gravitational-Wave Capture Sources in Galactic Nuclei: Distribution of Binary Parameters Authors: L\'aszl\'o Gond\'an, Bence Kocsis, P\'eter Raffai, Zsolt Frei Categories: astro-ph.HE gr-qc Comments: 27 pages, 12 figures, submitted to ApJ \\ Mergers of binary black holes on eccentric orbits are among the targets for second generation ground-based gravitational-wave detectors. These sources may commonly form in galactic nuclei due to gravitational-wave emission during close flyby events of single objects. We determine the distributions of initial orbital parameters for a population of these gravitational-wave sources. Our results show that the initial dimensionless pericenter distance systematically decreases with the binary component masses and the mass of the central supermassive black hole, and its distribution depend sensitively on the highest possible black hole mass in the nuclear star cluster. For a multi-mass black hole population with masses between 5 Msun and 80 Msun, more than 40% of sources have an eccentricity greater than 0.1 when the gravitational-wave signal reaches 10 Hz or if it forms at higher frequencies, but only 7% of the sources with binary component masses less than 30 Msun remain eccentric at this level near the last stable orbit (LSO). The eccentricity at LSO is typically between 0.005-0.05 for the lower mass BHs, and 0.1-0.2 for the highest mass BHs. Thus, due to the limited low-frequency sensitivity, the currently known six quasicircular LIGO/Virgo sources are compatible with this originally highly eccentric source population. At the design sensitivity of these instruments, the measurement of the eccentricity and mass distribution of merger events may be a useful diagnostic to distinguish among different astrophysical binary formation channels. \\ ( https://arxiv.org/abs/1711.09989 , 504kb) ------------------------------------------------------------------------------ \\ arXiv:1711.10037 (*cross-listing*) Date: Mon, 27 Nov 2017 23:18:55 GMT (3941kb,D) Title: Higher Spin de Sitter Hilbert Space Authors: Dionysios Anninos, Frederik Denef, Ruben Monten, Zimo Sun Categories: hep-th gr-qc \\ We propose a complete microscopic definition of the Hilbert space of minimal higher spin de Sitter quantum gravity and its Hartle-Hawking vacuum state. The fundamental degrees of freedom are $2N$ bosonic fields living on the future conformal boundary, where $N$ is proportional to the de Sitter horizon entropy. The vacuum state is normalizable. The model agrees in perturbation theory with expectations from a previously proposed dS-CFT description in terms of a fermionic Sp(N) model, but it goes beyond this, both in its conceptual scope and in its computational power. In particular it resolves the apparent pathologies affecting the Sp(N) model, and it provides an exact formula for late time vacuum correlation functions. We illustrate this by computing probabilities for arbitrarily large field excursions, and by giving fully explicit examples of vacuum 3- and 4-point functions. We discuss bulk reconstruction and show the perturbative bulk QFT canonical commutations relations can be reproduced from the fundamental operator algebra, but only up to a minimal error term $\sim e^{-\mathcal{O}(N)}$, and only if the operators are coarse grained in such a way that the number of accessible "pixels" is less than $\mathcal{O}(N)$. Independent of this, we show that upon gauging the higher spin symmetry group, one is left with $2N$ physical degrees of freedom, and that all gauge invariant quantities can be computed by a $2N \times 2N$ matrix model. This suggests a concrete realization of the idea of cosmological complementarity. \\ ( https://arxiv.org/abs/1711.10037 , 3941kb) ------------------------------------------------------------------------------ \\ arXiv:1711.10038 (*cross-listing*) Date: Mon, 27 Nov 2017 23:20:12 GMT (2460kb,D) Title: Surprises from the spins: astrophysics and relativity with detections of spinning black-hole mergers Authors: Davide Gerosa Categories: astro-ph.HE gr-qc Comments: Proceedings of the 12th Amaldi conference on gravitational waves (Pasadena, CA, July 2016). Animated version of Fig. 2 available at https://davidegerosa.com/spinprecession \\ Measurements of black-hole spins are of crucial importance to fulfill the promise of gravitational-wave astronomy. On the astrophysics side, spins are perhaps the cleanest indicator of black-hole evolutionary processes, thus providing a preferred way to discriminate how LIGO's black holes form. On the relativity side, spins are responsible for peculiar dynamical phenomena (from precessional modulations in the long inspiral to gravitational-wave recoils at merger) which encode precious information on the underlying astrophysical processes. I present some examples to explore this deep and fascinating interplay between spin dynamics (relativity) and environmental effects (astrophysics). Black-hole spins indeed hide remarkable surprises on both fronts: morphologies, resonances, constraints on supernova kicks, multiple merger generations and more... \\ ( https://arxiv.org/abs/1711.10038 , 2460kb) ------------------------------------------------------------------------------ \\ arXiv:1711.10424 (*cross-listing*) Date: Tue, 28 Nov 2017 17:31:16 GMT (21kb) Title: On the 6th Mode in Massive Gravity Authors: Marco Celoria, Marco Celoria, Luigi Pilo Categories: hep-th astro-ph.CO gr-qc Comments: Latex 17 pages \\ Generic massive gravity models in the unitary gauge correspond to a self-gravitating medium with six degrees of freedom. It is widely believed that massive gravity models with six degrees of freedom have an unavoidable ghost-like instability; however, the corresponding medium has stable phonon-like excitations. The apparent contradiction is solved by the presence of a non-vanishing background pressure and energy density of the medium that opens up a stability window. The result is confirmed by looking at linear stability on an expanding Universe, recovering the flat space stability conditions in the small wavelength limit. Moreover, one can show that under rather mild conditions, no ghost-like instability is present for any wavelength. As a result, exploiting the medium interpretation, a generic massive gravity model with six degrees of freedom is perfectly viable. \\ ( https://arxiv.org/abs/1711.10424 , 21kb) ------------------------------------------------------------------------------ \\ arXiv:1711.10458 (*cross-listing*) Date: Tue, 28 Nov 2017 18:45:11 GMT (857kb,D) Title: Seven Hints for Primordial Black Hole Dark Matter Authors: Sebastien Clesse, Juan Garc\'ia-Bellido Categories: astro-ph.CO astro-ph.GA gr-qc hep-th Comments: 11 pages, 3 figures, comments welcome Report-no: IFT-UAM/CSIC-17-108, CERN-TH-2017-239 \\ The detection by Advanced LIGO/VIRGO of black hole mergers with large progenitor masses ranging up to 30 $M_\odot$ and one progenitor spin likely to be non-aligned with the orbital momentum, point towards a possible primordial (non-stellar) origin of these black holes. If they are primordial black holes (PBH), the merger rates inferred by LIGO coincide with the ones expected for abundances comparable to those of Dark Matter (DM). By re-investigating some observations, such as microlensing and compact star clusters in faint dwarf galaxies, and by analyzing the latest LIGO data, we identify seven hints pointing towards PBH-DM, with a broad mass spectrum centered in the range $[1-10] M_\odot$. The detection of numerous micro-lensing events of distant quasars and stars in M31 provide firm evidences that 15%-25% of the halo of massive galaxies is made of compact objects with masses $[0.05-0.45] M_\odot$ and $[0.5-1] M_\odot$ respectively, such as a primordial black holes. These values are compatible with the re-constructed PBH mass spectrum from LIGO events. Altogether, for a log-normal distribution, we find best fit values for the central mass $\mu \approx 3 M_\odot$ and a width $ \sigma \approx 0.5 $. On the other hand, this scenario passes all the other current constraints on PBH abundances. Moreover, we show by using first physical principles that it would naturally explain the missing dwarf satellites, too-big-to-fail, core/cusp and missing baryon problems as well as the observation of super-massive black holes at high redshifts that would have grown from primordial seeds in the tail of the PBH mass distribution. In this scenario, between 0.1% and 1% of the events detected by LIGO will involve a PBH with a mass below the Chandrasekhar mass, which would unambiguously prove the existence of PBH. \\ ( https://arxiv.org/abs/1711.10458 , 857kb) ------------------------------------------------------------------------------ \\ arXiv:1711.10472 (*cross-listing*) Date: Tue, 28 Nov 2017 18:59:29 GMT (505kb,D) Title: Massive gravity and the suppression of anisotropies and gravitational waves in a matter-dominated contracting universe Authors: Chunshan Lin, Jerome Quintin, Robert H. Brandenberger Categories: hep-th astro-ph.CO gr-qc hep-ph Comments: 20 pages, 2 figures \\ We consider a modified gravity model with a massive graviton, but which nevertheless only propagates two gravitational degrees of freedom and which is free of ghosts. We show that non-singular bouncing cosmological background solutions can be generated. In addition, the mass term for the graviton prevents anisotropies from blowing up in the contracting phase and also suppresses the spectrum of gravitational waves compared to that of the scalar cosmological perturbations. This addresses two of the main problems of the matter bounce scenario. \\ ( https://arxiv.org/abs/1711.10472 , 505kb) ------------------------------------------------------------------------------ \\ arXiv:1711.10474 (*cross-listing*) Date: Tue, 28 Nov 2017 18:59:59 GMT (94kb,D) Title: Asymptotically-flat supergravity solutions deep inside the black-hole regime Authors: Iosif Bena, Stefano Giusto, Emil J. Martinec, Rodolfo Russo, Masaki Shigemori, David Turton and Nicholas P. Warner Categories: hep-th gr-qc Comments: 49 pages, 3 figures Report-no: IPHT-T17/135, QMUL-PH-17-26, YITP-17-127 \\ We construct an infinite family of smooth asymptotically-flat supergravity solutions that have the same charges and angular momenta as general supersymmetric D1-D5-P black holes, but have no horizon. These solutions resemble the corresponding black hole to arbitrary accuracy outside of the horizon: they have asymptotically flat regions, AdS_3 x S^3 throats and very-near-horizon AdS_2 throats, which however end in a smooth cap rather than an event horizon. The angular momenta of the solutions are general, and in particular can take arbitrarily small values. Upon taking the AdS_3 x S^3 decoupling limit, we identify the holographically-dual CFT states. \\ ( https://arxiv.org/abs/1711.10474 , 94kb) %%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%% ------------------------------------------------------------------------------ \\ arXiv:1608.07521 replaced with revised version Tue, 28 Nov 2017 16:59:08 GMT (55kb,D) Title: Unique continuation from infinity in asympotically Anti-de Sitter spacetimes II: Non-static boundaries Authors: Gustav Holzegel, Arick Shao Categories: gr-qc math.AP Comments: 45 pages. Newest version incorporated changes from referee comments and fixed minor typos MSC-class: 35A02, 35Q75, 83C30, 35L05 DOI: 10.1080/03605302.2017.1390677 \\ ( https://arxiv.org/abs/1608.07521 , 55kb) ------------------------------------------------------------------------------ \\ arXiv:1701.01383 replaced with revised version Mon, 27 Nov 2017 19:26:58 GMT (151kb,D) Title: Group Field theory and Tensor Networks: towards a Ryu-Takayanagi formula in full quantum gravity Authors: Goffredo Chirco, Daniele Oriti, Mingyi Zhang Categories: gr-qc cond-mat.stat-mech hep-th quant-ph Comments: 54 pages, 10 figures; v2: replace figure 1 with a new version. Matches submitted version. v3: remove Renyi entropy computation on the random tensor network, focusing on GFT computation and interpretation \\ ( https://arxiv.org/abs/1701.01383 , 151kb) ------------------------------------------------------------------------------ \\ arXiv:1705.00730 replaced with revised version Mon, 27 Nov 2017 19:20:58 GMT (432kb,D) Title: Exact Geodesic Distances in FLRW Spacetimes Authors: William J. Cunningham, David Rideout, James Halverson, and Dmitri Krioukov Categories: gr-qc astro-ph.CO math-ph math.MP Comments: 11 pages, 2 figures Journal-ref: Phys. Rev. D 96, 103538 (2017) DOI: 10.1103/PhysRevD.96.103538 \\ ( https://arxiv.org/abs/1705.00730 , 432kb) ------------------------------------------------------------------------------ \\ arXiv:1705.01510 replaced with revised version Tue, 28 Nov 2017 15:25:59 GMT (3523kb,D) Title: Deformation of horizons during a merger Authors: Uzair Hussain and Ivan Booth Categories: gr-qc Comments: 22 pages, 7 figures \\ ( https://arxiv.org/abs/1705.01510 , 3523kb) ------------------------------------------------------------------------------ \\ arXiv:1705.04861 (*cross-listing*) replaced with revised version Tue, 28 Nov 2017 11:11:39 GMT (976kb,D) Title: Primordial Black Hole production in Critical Higgs Inflation Authors: Jose Maria Ezquiaga, Juan Garcia-Bellido, Ester Ruiz Morales Categories: astro-ph.CO gr-qc hep-ph hep-th Comments: 6 pages, 3 figures. Matches PLB version Report-no: IFT-UAM/CSIC-17-043 \\ ( https://arxiv.org/abs/1705.04861 , 976kb) ------------------------------------------------------------------------------ \\ arXiv:1705.09836 replaced with revised version Tue, 28 Nov 2017 09:34:49 GMT (11kb) Title: The continuum approach to the BF vacuum: the U(1) case Authors: Patryk Drobi\'nski, Jerzy Lewandowski Categories: gr-qc Comments: 13 pages \\ ( https://arxiv.org/abs/1705.09836 , 11kb) ------------------------------------------------------------------------------ \\ arXiv:1706.04434 replaced with revised version Mon, 27 Nov 2017 20:28:49 GMT (13kb) Title: Braneworld Black Holes and Entropy Bounds Authors: Y. Heydarzade, H. Hadi, C. Corda and F. Darabi Categories: gr-qc astro-ph.HE hep-th Comments: 13 pages, accepted for publication in Physics Letters B \\ ( https://arxiv.org/abs/1706.04434 , 13kb) ------------------------------------------------------------------------------ \\ arXiv:1706.08426 (*cross-listing*) replaced with revised version Tue, 28 Nov 2017 08:20:18 GMT (41kb) Title: The Hawking-Penrose singularity theorem for $C^{1,1}$-Lorentzian metrics Authors: Melanie Graf, James D.E. Grant, Michael Kunzinger, Roland Steinbauer Categories: math-ph gr-qc math.DG math.MP Comments: 35 pages, minor typographical corrections, final version MSC-class: 83C75, 53B30 \\ ( https://arxiv.org/abs/1706.08426 , 41kb) ------------------------------------------------------------------------------ \\ arXiv:1707.04172 replaced with revised version Tue, 28 Nov 2017 11:43:30 GMT (15kb) Title: Generalized Rainich conditions, generalized stress-energy conditions, and the Hawking-Ellis classification Authors: Prado Mart\'in-Moruno, Matt Visser Categories: gr-qc Comments: V1: 20 pages. V2: Matches published version, now 18 pages (new format), minor clarifications added Journal-ref: Classical and Quantum Gravity 34 (2017) 225014 DOI: 10.1088/1361-6382/aa9039 \\ ( https://arxiv.org/abs/1707.04172 , 15kb) ------------------------------------------------------------------------------ \\ arXiv:1708.04837 (*cross-listing*) replaced with revised version Tue, 28 Nov 2017 08:04:43 GMT (287kb,D) Title: Neutron stars in the braneworld within the Eddington-inspired Born-Infeld gravity Authors: I. Prasetyo, I. Husin, A. I. Qauli, H. S. Ramadhan, A. Sulaksono Categories: astro-ph.CO gr-qc Comments: 20 pages, 8 figures \\ ( https://arxiv.org/abs/1708.04837 , 287kb) ------------------------------------------------------------------------------ \\ arXiv:1708.06371 replaced with revised version Tue, 28 Nov 2017 18:38:53 GMT (275kb) Title: On Bouncing and Nonsingular Solutions in Einstein-scalar-Gauss-Bonnet Cosmology Authors: Laura Sberna and Paolo Pani Categories: gr-qc Comments: 9 pages, 4 figures; references and discussion added; further minor revision, accepted to PRD \\ ( https://arxiv.org/abs/1708.06371 , 275kb) ------------------------------------------------------------------------------ \\ arXiv:1708.06869 replaced with revised version Tue, 28 Nov 2017 03:39:43 GMT (1350kb) Title: Hawking radiation-quasinormal modes correspondence for large AdS black holes Authors: Dao-Quan Sun, Zi-Liang Wang, Miao He, Xian-Ru Hu, Jian-Bo Deng Categories: gr-qc Comments: 6 pages Journal-ref: Advances in High Energy Physics Volume 2017 DOI: 10.1155/2017/4817948 \\ ( https://arxiv.org/abs/1708.06869 , 1350kb) ------------------------------------------------------------------------------ \\ arXiv:1709.00157 replaced with revised version Tue, 28 Nov 2017 01:07:54 GMT (642kb) Title: Analytical Study of Charged Boson Stars with Large Scalar Self-couplings Authors: Nahomi Kan, Kiyoshi Shiraishi Categories: gr-qc hep-th Comments: 20 pages, 13 figures. minor revision \\ ( https://arxiv.org/abs/1709.00157 , 642kb) ------------------------------------------------------------------------------ \\ arXiv:1709.02643 (*cross-listing*) replaced with revised version Tue, 28 Nov 2017 09:42:53 GMT (206kb) Title: Modeling differential rotations of compact stars in equilibriums Authors: Koji Uryu, Antonios Tsokaros, Luca Baiotti, Filippo Galeazzi, Keisuke Taniguchi, Shin'ichirou Yoshida Categories: astro-ph.HE gr-qc Comments: 7 pages, 4 figures Journal-ref: Phys. Rev. D 96, 103011 (2017) DOI: 10.1103/PhysRevD.96.103011 \\ ( https://arxiv.org/abs/1709.02643 , 206kb) ------------------------------------------------------------------------------ \\ arXiv:1711.01296 (*cross-listing*) replaced with revised version Tue, 28 Nov 2017 02:28:15 GMT (833kb,D) Title: The classical double copy in maximally symmetric spacetimes Authors: Mariana Carrillo-Gonzalez, Riccardo Penco, Mark Trodden Categories: hep-th gr-qc Comments: references added \\ ( https://arxiv.org/abs/1711.01296 , 833kb) ------------------------------------------------------------------------------ \\ arXiv:1711.05514 replaced with revised version Tue, 28 Nov 2017 16:25:54 GMT (2113kb,D) Title: Models of Exotic Interferometer Cross-Correlations in Emergent Space-Time Authors: Craig Hogan and Ohkyung Kwon Categories: gr-qc quant-ph Comments: 25 pages, 13 figures Report-no: FERMILAB-PUB-17-481-A \\ ( https://arxiv.org/abs/1711.05514 , 2113kb) ------------------------------------------------------------------------------ \\ arXiv:1711.06628 replaced with revised version Tue, 28 Nov 2017 11:49:19 GMT (85kb,D) Title: Probing extra dimensions with gravitational and electromagnetic signals from compact mergers Authors: Luca Visinelli, Nadia Bolis, and Sunny Vagnozzi Categories: gr-qc astro-ph.CO Comments: 7 pages, 3 figures. Version submitted to PRD \\ ( https://arxiv.org/abs/1711.06628 , 85kb) ------------------------------------------------------------------------------ \\ arXiv:1711.07903 (*cross-listing*) replaced with revised version Tue, 28 Nov 2017 15:43:45 GMT (34kb,D) Title: Diffusion in higher dimensional SYK model with complex fermions Authors: Wenhe Cai, Xian-Hui Ge, Guo-Hong Yang Categories: hep-th cond-mat.str-el gr-qc Comments: 15 pages, 1 figure, add 4 references and fix some typos in this version \\ ( https://arxiv.org/abs/1711.07903 , 34kb) ------------------------------------------------------------------------------ \\ arXiv:1711.09071 (*cross-listing*) replaced with revised version Tue, 28 Nov 2017 01:56:13 GMT (3kb) Title: Working with Stephen Authors: James B. Hartle Categories: physics.hist-ph gr-qc hep-th \\ ( https://arxiv.org/abs/1711.09071 , 3kb) %%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%--- 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/