Format results
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An effective density matrix for vacua in asymptotically flat gravity
Temple He - California Institute of Technology (Caltech)
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Area as a quantum reference frame
Joshua Kirklin - Perimeter Institute for Theoretical Physics
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Light-cone formulation and Carrollian Physics
Sucheta Majumdar - École Normale Supérieure de Lyon (ENS Lyon)
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The operational meaning of total energy in general relativity
Simone Speziale - Aix-Marseille University
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What are the `axioms’ of General Relativity? Ask Quantum Gravity!
Fay Dowker - Imperial College London
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Quantum Gravity and Effective Topology
Renate Loll - Radboud Universiteit Nijmegen
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Numerical Methods in (Loop) Quantum Gravity
Dongxue Qu - Chengdu University of Technology
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An effective density matrix for vacua in asymptotically flat gravity
Temple He - California Institute of Technology (Caltech)
We explicitly construct the density matrix associated to the vacuum state of a large spherically symmetric causal diamond in four-dimensional asymptotically flat gravity. We achieve this using the soft effective action, which characterizes the low-energy gravitational degrees of freedom that arise… -
Area as a quantum reference frame
Joshua Kirklin - Perimeter Institute for Theoretical Physics
Elementary quantum reference frames (QRFs) such as clocks have recently led to surprising insights into quantum gravity. But far richer structures should emerge once we consider more full-fledged gravitational QRFs, i.e. quantum coordinate systems. A complete theory of such objects remains elusive… -
Light-cone formulation and Carrollian Physics
Sucheta Majumdar - École Normale Supérieure de Lyon (ENS Lyon)
Motivated by recent advances in "non-Lorentzian" physics, I will revisit the light-cone formulation of QFT, which has played a central role in the quantization of gauge theories. Much of its success can be traced to the presence of an underlying non-relativistic (Galilean) structure within the light… -
The operational meaning of total energy in general relativity
Simone Speziale - Aix-Marseille University
The ADM and Bondi energies are key examples of observables in general relativity. They have played a crucial role to clarify the meaning of gravitational energy, and by Noether's theorem, to understand (boundary) symmetries. In spite of their conceptual importance, they are not directly measurable… -
What are the `axioms’ of General Relativity? Ask Quantum Gravity!
Fay Dowker - Imperial College London
The good books on GR agree on certain aspects of the theory that we could consider to be its “core” features. Beyond the core, however, we do not know exactly what GR should allow or not allow physically. For example, should we consider spacetimes with closed causal loops as part of physical GR or… -
Understanding the information loss paradox: Three facts and one hypothesis from Euclidean and canonical quantum gravity
Dong-ham Yeom - Pusan National University
The first part of the talk will briefly discuss the tasks that need to be accomplished in order to formulate such open quantum models in the context of quantum gravity, as well as the challenges involved. As a first step in this direction, a QFT model in the context of linearised gravity is… -
Gravitationally induced decoherence: From theoretical models to applications in neutrino oscillations
Kristina Giesel
Models for gravitationally induced decoherence can be formulated within the framework of open quantum systems, in which gravity is chosen as the environment and quantised together with the system under consideration. The effective dynamics of the system under the influence of the environment are… -
Probing Quantum Features of Gravity in Tabletop Regime and Reassessing the I.I.D. Assumption in Quantum Probability Assignments
Linqing Chen - Austrian Academy of Sciences
Recent advancements in tabletop experiments may offer the first empirical proof that gravity is not classical. In the first part of my talk, I will present two effects that overcome the current limitations of Newton potential phenomenology, involving generic quantum sources of gravity. These effects… -
Flatness and spikes in Ponzano-Regge
The original spinfoam amplitude, Ponzano-Regge, has two properties in seeming contradiction: (1.) It can be written as an integral of a product of Dirac delta functions imposing that holonomies be exactly flat, and (2.) In its original sum-over-spins form, its leading order large spin asymptotics… -
Quantum Gravity and Effective Topology
Renate Loll - Radboud Universiteit Nijmegen
My presentation will introduce a new methodology to characterize properties of quantum spacetime in a strongly quantum-fluctuating regime, using tools from topological data analysis. Starting from a microscopic quantum geometry, generated nonperturbatively in terms of dynamical triangulations (DT)… -
Detecting single gravitons with gravitational wave detectors
The quantization of gravity is widely believed to result in gravitons -- particles of discrete energy that form gravitational waves. But their detection has so far been considered impossible. In this talk, I will show that laboratory experiments can reveal signatures of single graviton exchange. I… -
Numerical Methods in (Loop) Quantum Gravity
Dongxue Qu - Chengdu University of Technology
Numerical methods are powerful tools for advancing our understanding of quantum gravity. In this talk, I will introduce two complementary numerical approaches. The first focuses on solving nonlinear partial differential equations that arise in Loop Quantum Gravity (LQG)-inspired effective models…