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.
Switching internal times and a new perspective on the 'wave function of the universe'
5 Pith papers cite this work. Polarity classification is still indexing.
abstract
Despite its importance in general relativity, a quantum notion of general covariance has not yet been established in quantum gravity and cosmology, where, given the a priori absence of coordinates, it is necessary to replace classical frames with dynamical quantum reference systems. As such, quantum general covariance bears on the ability to consistently switch between the descriptions of the same physics relative to arbitrary choices of quantum reference system. Recently, a systematic approach for such switches has been developed (arXiv:1809.00556, 1809.05093, 1810.04153). It links the descriptions relative to different choices of quantum reference system, identified as the correspondingly reduced quantum theories, via the reference-system-neutral Dirac quantization, in analogy to coordinate changes on a manifold. In this work, we apply this method to a simple cosmological model to demonstrate how to consistently switch between different internal time choices in quantum cosmology. We substantiate the argument that the conjunction of Dirac and reduced quantized versions of the theory defines a complete relational quantum theory that not only admits a quantum general covariance, but, we argue, also suggests a new perspective on the 'wave function of the universe'. It assumes the role of a perspective-neutral global state, without immediate physical interpretation, that, however, encodes all the descriptions of the universe relative to all possible choices of reference system at once and constitutes the crucial link between these internal perspectives. While, for simplicity, we use the Wheeler-DeWitt formulation, the method and arguments might be also adaptable to loop quantum cosmology.
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Extends quantum reference frames to quantum reference fields in linearized quantum gravity and derives unitary maps implementing relational gauge-invariant observables between quantum perspectives.
In no-roll quantum cosmology, fixing the integration constant for potential energy yields a one-dimensional Hilbert space selecting Vilenkin's tunnelling wavefunction, while arbitrary values permit an infinite-dimensional space with a one-parameter family of boundary conditions at the singularity th
Algebraic entanglement entropy from type II1 algebras in double-scaled SYK is matched via triple-scaling limits to Ryu-Takayanagi areas in (A)dS2, reproducing Bekenstein-Hawking and Gibbons-Hawking formulas for specific regions while depending on Krylov complexity of the Hartle-Hawking state.
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
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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Quantum Reference Fields Transformations in Linearized Quantum Gravity
Extends quantum reference frames to quantum reference fields in linearized quantum gravity and derives unitary maps implementing relational gauge-invariant observables between quantum perspectives.
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Boundary conditions and Hilbert spaces in no-roll quantum cosmology
In no-roll quantum cosmology, fixing the integration constant for potential energy yields a one-dimensional Hilbert space selecting Vilenkin's tunnelling wavefunction, while arbitrary values permit an infinite-dimensional space with a one-parameter family of boundary conditions at the singularity th
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Cosmological Entanglement Entropy from the von Neumann Algebra of Double-Scaled SYK & Its Connection with Krylov Complexity
Algebraic entanglement entropy from type II1 algebras in double-scaled SYK is matched via triple-scaling limits to Ryu-Takayanagi areas in (A)dS2, reproducing Bekenstein-Hawking and Gibbons-Hawking formulas for specific regions while depending on Krylov complexity of the Hartle-Hawking state.
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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