Bulletin of the American Physical Society
APS April Meeting 2023
Volume 68, Number 6
Minneapolis, Minnesota (Apr 15-18)
Virtual (Apr 24-26); Time Zone: Central Time
Session UU02: V: Quantum Gravity and Beyond |
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Sponsoring Units: DGRAV Chair: Eduardo Martin Martinez Room: Virtual Room 2 |
Tuesday, April 25, 2023 6:00PM - 6:12PM |
UU02.00001: Dynamics and entanglement in quantum and quantum-classical systems: lessons for gravity Irfan Javed Motivated by quantum gravity, semiclassical theory, and quantum theory on curved spacetimes, we study the system of an oscillator coupled to two spin-1/2 particles. This model provides a prototype for comparing three types of dynamics: the full quantum theory, the classical oscillator with spin backreaction, and spins propagating on a fixed oscillator background. From calculations of oscillator and entanglement entropy evolution, we find the three systems give equivalent dynamics for sufficiently weak oscillator-spin couplings but deviate significantly for intermediate couplings. These results suggest that semiclassical dynamics with backreaction does not provide a suitable intermediate regime between quantum gravity and quantum theory on curved spacetime. |
Tuesday, April 25, 2023 6:12PM - 6:24PM |
UU02.00002: Two-dimensional Topology in Combinatorial Emergent Gravity Kassahun H Betre Combinatorial Emergent Gravity is an attempt towards non-perturbative description of quantum gravity where one explores ways in which geometry and gravitational dynamics emerge from non-geometric relational quantum microstates defined using combinatorial objects such as simple graphs. A microscopic dynamics is postulated to exist such that the topology and geometry of spacetime will emerge in the low-temperature phase of the system. We describe a model with a Hamiltonian that is quartic in the adjacency matrix of the graphs placed in a canonical ensemble of all simple graphs of a fixed vertex count. A simulated-annealing and parallel tempering algorithms are utilized to explore the ground states and finite-temperature phases of the system. The system is found to have two-dimensional geometric graphs as the ground states. |
Tuesday, April 25, 2023 6:24PM - 6:36PM |
UU02.00003: Semiclassical Dynamics of Hawking Radiation David Lowe, Larus Thorlacius The problem of solving the equations for Hawking radiation, with full backreaction included, is cast as an initial value problem suitable for future numerical simulations. Quantum entanglement of the fields is captured using bilocal collective fields in a large N limit. Corrections to the Einstein equations contain up to four spacetime derivatives. These corrections are treated systematically using perturbative constraints. |
Tuesday, April 25, 2023 6:36PM - 6:48PM |
UU02.00004: Are all black holes dual to 2 dimensional conformal field theories (2D CFTs)? Maria J Rodriguez Holographic dualities between certain gravitational theories in four and five spacetime dimensions and 2D conformal field theories (CFTs) have been proposed based on hidden conformal symmetry exhibited by the radial Klein-Gordon (KG) operator in a so-called near-region limit. In this talk, we examine hidden conformal symmetry of 5-dimensioal black hole solutions, thus demonstrating that the presence of hidden conformal symmetry is not linked to the separability of the KG-equation (or the existence of a Killing-Yano tensor). Further, we will argue that these classes of non-extremal black holes have a dual 2D CFT. |
Tuesday, April 25, 2023 6:48PM - 7:00PM |
UU02.00005: Spatial carrier distribution, Energy subbands, and Potential profile calculation of a conducting interface LaVO3/SrTiO3 using optical and transport measurement. Anamika Kumari The carrier-density distribution near a conducting interface and related band structure is an essential topic of condensed matter physics. We propose a scheme combining Photoluminescence (PL) spectroscopy, time-correlated photon counting (TCSPC) with electrical measurements to reveal the distribution of the carriers, the shape of the quantum well, energy subbands, and Fermi surfaces of the conducting interface of LaVO3 and SrTiO3 (LVO/STO). Electronic properties such as carrier density, and mobility estimated from the electrical measurements are in excellent agreement with that estimated from optical spectroscopy-based methods through theoretical modeling. The proper knowledge of band structure can help us to understand the fascinating physics of “Rashba band splitting” due to high spin-orbit coupling which gives rise to the planar hall effect, non-trivial berry phase, etc. |
Tuesday, April 25, 2023 7:00PM - 7:12PM |
UU02.00006: Rate Change Science of Two Gravity Waves Kenneth Strickland An application in Rate Change Science (RCS) proves the reality of two gravity waves in our universe. It should not be astounding at all. The clues and evidence have been available for over twenty years. The ultimate truth is the modernization of “rate of change” science that creates a wealth of new knowledge from basics to our ultimate endeavor. RCS reorganizes, redefines and repackages physics into 22st century science. The benefits are faster turnaround on theory legitimacy, more exact equations of measurement and a huge saving on project time. See for the first time a derivative universe where all things geometrical are observed. |
Tuesday, April 25, 2023 7:12PM - 7:24PM |
UU02.00007: Gravity as Variation into Scalar Field Density in Universal Mechanics Surendra Mund In this APS April Meeting, 2022, I intend to present a new definition of Gravitation like interaction which works on all type of central systems exist according to my N-Time Inflationary Model of Universe. I have described gravitation and strong nuclear type of interactions under variational interactions. Each and every type of body exist in universe have some variation into scalar field density around themselves, and this variation inserts a force on any type of body, the strength can be different for different type of scalar field densities. The variational type of interaction is very fundamental and crucial component of each and every type of central system exist in universe. |
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