Bulletin of the American Physical Society
APS April Meeting 2016
Volume 61, Number 6
Saturday–Tuesday, April 16–19, 2016; Salt Lake City, Utah
Session E15: Quantum Aspects of Gravitation I |
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Sponsoring Units: GGR Chair: Deborah Konkowski, United States Naval Academy Room: 251C |
Saturday, April 16, 2016 3:30PM - 3:42PM |
E15.00001: Unitarization of black hole decay Steven Giddings I overview some constraints on scenarios that can unitarize black hole disintegration, and also discuss the possibility of finding signatures of such scenarios in upcoming observations of supermassive black holes. [Preview Abstract] |
Saturday, April 16, 2016 3:42PM - 3:54PM |
E15.00002: Dimensional Reduction in Causal Set Gravity Steven Carlip Several different approaches to quantum gravity indicate that the effective dimension of spacetime falls to approximately two at very short distances. I provide evidence for similar behavior in the causal set approach to quantum gravity. [Preview Abstract] |
Saturday, April 16, 2016 3:54PM - 4:06PM |
E15.00003: Maximal vacuum entanglement principle Ted Jacobson I will discuss evidence supporting the hypothesis that entanglement entropy in small geodesic balls is maximal at fixed volume [1]. This is in a sense a microscopic version of the holographic principle, and the evidence for its validity hinges on the Einstein equation. I will also discuss the effort to derive the Einstein equation by assuming the hypothesis is valid, and some relevant results about entanglement variation [2,3,4].\\ \vskip 2mm \noindent [1] Ted Jacobson, arXiv/1505.04753\ [2] Horacio Casini, Damian A. Galante, Robert C. Myers, arXiv/1601.00528\ [3] Antony Speranza, in preparation\ [4] Madhavan Varadarajan, in preparation\ [Preview Abstract] |
Saturday, April 16, 2016 4:06PM - 4:18PM |
E15.00004: Four-dimensional Quantum Gravity with a Cosmological Constant from Three-dimensional Holomorphic Blocks Hal Haggard, Muxin Han, Wojciech Kaminski, Aldo Riello Prominent approaches to quantum gravity struggle when it comes to incorporating a positive cosmological constant in their models. Using quantization of a complex SL(2,C) Chern-Simons theory we include a cosmological constant, of either sign, into a model of quantum gravity. [Preview Abstract] |
Saturday, April 16, 2016 4:18PM - 4:30PM |
E15.00005: Conformal Loop quantization of gravity coupled to the standard model Jorge Pullin, Rodolfo Gambini We consider a local conformal invariant coupling of the standard model to gravity free of any dimensional parameter. The theory is formulated in order to have a quantized version that admits a spin network description at the kinematical level like that of loop quantum gravity. The Gauss constraint, the diffeomorphism constraint and the conformal constraint are automatically satisfied and the standard inner product of the spin-network basis still holds. The resulting theory has resemblances with the Bars-Steinhardt-Turok local conformal theory, except it admits a canonical quantization in terms of loops. By considering a gauge fixed version of the theory we show that the Standard model coupled to gravity is recovered and the Higgs boson acquires mass. This in turn induces via the standard mechanism masses for massive bosons, baryons and leptons.. [Preview Abstract] |
Saturday, April 16, 2016 4:30PM - 4:42PM |
E15.00006: The Necessity of Quantizing Gravity Jeremy Adelman The Eppley Hannah thought experiment is often cited as justification for attempts by theorists to develop a complete, consistent theory of quantum gravity. A modification of the earlier "Heisenberg microscope" argument for the necessity of quantized light, the Eppley-Hannah thought experiment purports to show that purely classical gravitational waves would either not conserve energy or else allow for violations of the uncertainty principle. However, several subsequent papers have cast doubt as to the validity of the Eppley-Hannah argument. In this talk, we will show how to resurrect the Eppley-Hannah thought experiment by modifying the original argument in a way that gets around the present criticisms levied against it. [Preview Abstract] |
Saturday, April 16, 2016 4:42PM - 4:54PM |
E15.00007: Tunneling of squeezed states with an eye to evaporating black holes Eleni-Alexandra Kontou, Hal Haggard In this work we study how tunneling time depends on the squeezing parameter of quantum states. Squeezed quantum states are investigated for optical communications and appear in the emission from black holes. A surprising property of these states is reduced tunneling time. Treating Hawking radiation as a quantum tunneling process, we study the interplay of squeezing with the radiation process. [Preview Abstract] |
Saturday, April 16, 2016 4:54PM - 5:06PM |
E15.00008: Quantum Gravitational Force Between Polarizable Objects Mark Hertzberg, Larry Ford, Johanna Karouby Since general relativity is a consistent low energy effective field theory, it is possible to compute quantum corrections to classical forces. Here we compute a quantum correction to the gravitational potential between a pair of polarizable objects. We study two distant bodies and compute a quantum force from their induced quadrupole moments due to two graviton exchange. The effect is in close analogy to the Casimir-Polder and London-van der Waals forces between a pair of atoms from their induced dipole moments due to two photon exchange. The new effect is computed from the shift in vacuum energy of metric fluctuations due to the polarizability of the objects. We compute the potential energy at arbitrary distances compared to the wavelengths in the system, including the far and near regimes. In the far distance, or retarded, regime, the potential energy takes on a particularly simple form: $V(r)=-3987\,\hbar\,c\,G^2\alpha_{1S}\,\alpha_{2S}/(4\,\pi\,r^{11})$, where $\alpha_{1S},\,\alpha_{2S}$ are the static gravitational quadrupole polarizabilities of each object. We provide estimates of this effect. [Preview Abstract] |
Saturday, April 16, 2016 5:06PM - 5:18PM |
E15.00009: Generalized information (entanglement) entropies depending on the probability (density matrix), (modified gravity). Octavio Obregón, Nana Geraldine Cabo Bizet Generalized information (entanglement) entropy(ies) that depend only on the probability (the density matrix) will be exhibited. It will be shown that these generalized information entropy(ies) are obtained by means of the superstatistics proposal and they correspond to generalized entanglement entropy(ies) that are at the same time a consequence of generalizing the Replica trick. Following the entropic force formulation, these generalized entropy(ies) provide a modified Newton´s law of gravitation. We discuss the difficulties to get an associated theory of gravity. Moreover, our results show corrections to the von Neumann entropy $S_{0}$ that are larger than the usual UV ones and also than the corrections to the length dependent $AdS_{3}$ entropy which result comparable to the UV ones. The correction terms due to the new entropy would modify the Ryu-Takayanagi identification between the CFT and the gravitational $AdS_{3}$ entropies. [Preview Abstract] |
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