Gravitational null rays are quantized in a diffeomorphism-covariant way using the gravitational dressing time as quantum reference frame, producing a Virasoro crossed-product algebra of gauge-invariant observables.
Observables, gravitational dressing, and obstructions to locality and subsystems
5 Pith papers cite this work. Polarity classification is still indexing.
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abstract
Quantum field theory - our basic framework for describing all non-gravitational physics - conflicts with general relativity: the latter precludes the standard definition of the former's essential principle of locality, in terms of commuting local observables. We examine this conflict more carefully, by investigating implications of gauge (diffeomorphism) invariance for observables in gravity. We prove a dressing theorem, showing that any operator with nonzero Poincare charges, and in particular any compactly-supported operator, in flat-spacetime quantum field theory must be gravitationally dressed once coupled to gravity, i.e. it must depend on the metric at arbitrarily long distances, and we put lower bounds on this nonlocal dependence. This departure from standard locality occurs in the most severe way possible: in perturbation theory about flat spacetime, at leading order in Newton's constant. The physical observables in a gravitational theory therefore do not organize themselves into local commuting subalgebras: the principle of locality must apparently be reformulated or abandoned, and in fact we lack a clear definition of the coarser and more basic notion of a quantum subsystem of the Universe. We discuss relational approaches to locality based on diffeomorphism-invariant nonlocal operators, and reinforce arguments that any such locality is state-dependent and approximate. We also find limitations to the utility of bilocal diffeomorphism-invariant operators that are considered in cosmological contexts. An appendix provides a concise review of the canonical covariant formalism for gravity, instrumental in the discussion of Poincare charges and their associated long-range fields.
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Constructs a phase space for gravitational degrees of freedom on null ray segments with commuting localized observables via edge modes and dressing time, then introduces an effective classical theory with Virasoro deformations to capture diffeomorphism anomalies and distinguish gauge, physical, and
A semiclassical construction of fiducial observers in JT gravity, fixed by conformal isometry flow, is extended to the quantum regime to compute wormhole contributions yielding finite thermal entropy and a quantum description of the stretched horizon.
In the Karch-Randall braneworld the zero-graviton-mass limit of the one-loop partition function is a massless graviton plus a decoupled massive vector, not the pure Randall-Sundrum II model.
Dressed relational observables imply quasi-de Sitter space corresponds to Type II_∞ von Neumann algebra with diverging trace in the gravity decoupling limit, unlike the finite-trace Type II_1 algebra for de Sitter space.
citing papers explorer
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Gravitational null rays: Covariant Quantization and the Dressing Time
Gravitational null rays are quantized in a diffeomorphism-covariant way using the gravitational dressing time as quantum reference frame, producing a Virasoro crossed-product algebra of gauge-invariant observables.
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Localization and anomalous reference frames in gravity
Constructs a phase space for gravitational degrees of freedom on null ray segments with commuting localized observables via edge modes and dressing time, then introduces an effective classical theory with Virasoro deformations to capture diffeomorphism anomalies and distinguish gauge, physical, and
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Fiducial observers and the thermal atmosphere in the black hole quantum throat
A semiclassical construction of fiducial observers in JT gravity, fixed by conformal isometry flow, is extended to the quantum regime to compute wormhole contributions yielding finite thermal entropy and a quantum description of the stretched horizon.
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Covariant Locally Localized Gravity and vDVZ Continuity
In the Karch-Randall braneworld the zero-graviton-mass limit of the one-loop partition function is a massless graviton plus a decoupled massive vector, not the pure Randall-Sundrum II model.
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Implication of dressed form of relational observable on von Neumann algebra
Dressed relational observables imply quasi-de Sitter space corresponds to Type II_∞ von Neumann algebra with diverging trace in the gravity decoupling limit, unlike the finite-trace Type II_1 algebra for de Sitter space.