15 citations · 103 across the 17 of their papers we have counts for
17 papers
Gravitational null rays: Covariant Quantization and the Dressing Time
Laurent Freidel, Josh Kirklin
We quantize the degrees of freedom on a gravitational null ray segment in a fully gauge-invariant manner by using the dressing time as a quantum reference frame (QRF). Our work goe…
Fighting non-locality with non-locality: microcausality and boundary conditions in QED
Philipp A. Hoehn, Josh Kirklin
In gauge theories, globally charged observables necessarily depend non-locally on the kinematical fields, with this dependence extending to the asymptotic boundary of spacetime. De…
Localization and anomalous reference frames in gravity
Laurent Freidel, Josh Kirklin
In this work, we study the classical phase space for the gravitational degrees of freedom along a null ray. We construct gauge-invariant observables localized on a null ray segment…
Quantum Gravity, Hydrodynamics and Emergent Cosmology: A Collection of Perspectives
Jibril Ben Achour, Dario Benedetti, Martin Bojowald +17
This collection of perspective pieces captures recent advancements and reflections from a dynamic research community dedicated to bridging quantum gravity, hydrodynamics, and emerg…
Crossed products and quantum reference frames: on the observer-dependence of gravitational entropy
Julian De Vuyst, Stefan Eccles, Philipp A. Hoehn +1
A significant step towards a rigorous understanding of perturbative gravitational entropy was recently achieved by a series of works showing that a proper accounting of gauge invar…
Generalised second law beyond the semiclassical regime
Josh Kirklin
We prove that the generalised second law (GSL), with an appropriate modification, holds in perturbative gravity to all orders beyond the semiclassical limit and without a UV cutoff…
Linearization (in)stabilities and crossed products
Julian De Vuyst, Stefan Eccles, Philipp A. Hoehn +1
Modular crossed product algebras have recently assumed an important role in perturbative quantum gravity as they lead to an intrinsic regularization of entanglement entropies by in…
Gravitational entropy is observer-dependent
Julian De Vuyst, Stefan Eccles, Philipp A. Hoehn +1
In quantum gravity, it has been argued that a proper accounting of the role played by an observer promotes the von Neumann algebra of observables in a given spacetime subregion fro…
Probes, purviews, purgatories, parable, paradox?
Josh Kirklin
I discuss some general information-theoretic properties of quantum mechanical probes in semiclassical gravity: their purview, i.e. what they can see and act on (in terms of a gener…
Emergent classical gauge symmetry from quantum entanglement
Josh Kirklin
We describe explicitly how entanglement between quantum mechanical subsystems can lead to emergent gauge symmetry in a classical limit. We first provide a precise characterisation…
Diffeomorphism-invariant observables and dynamical frames in gravity: reconciling bulk locality with general covariance
Christophe Goeller, Philipp A. Hoehn, Josh Kirklin
We describe a completely general and fully non-perturbative framework for constructing dynamical reference frames in generally covariant theories, and for understanding the gauge-i…
Islands and Uhlmann phase: Explicit recovery of classical information from evaporating black holes
Josh Kirklin
Recent work has established a route towards the semiclassical validity of the Page curve, and so provided evidence that information escapes an evaporating black hole. However, a pr…
Holography from Decoherence and Entanglement
Josh Kirklin
We describe an explicit mechanism for the emergence of a dynamical holographic bulk from the structure of entanglement in a quantum state. We start with a generic system in complet…
The Holographic Dual of the Entanglement Wedge Symplectic Form
Josh Kirklin
In this paper, we find the boundary dual of the symplectic form for the bulk fields in any entanglement wedge. The key ingredient is Uhlmann holonomy, which is a notion of parallel…
Unambiguous Phase Spaces for Subregions
Josh Kirklin
The covariant phase space technique is a powerful formalism for understanding the Hamiltonian description of covariant field theories. However, applications of this technique to pr…
Subregions, Minimal Surfaces, and Entropy in Semiclassical Gravity
Josh Kirklin
For a large class of density matrices in semiclassical gravity, it is shown that the reduced density matrix which corresponds to tracing over the degrees of freedom in a spatial su…
Localisation of Soft Charges, and Thermodynamics of Softly Hairy Black Holes
Josh Kirklin
Large gauge transformations (LGT) in asymptotically flat space are generated by charges defined at asymptotic infinity. No method for unambiguously localising these charges into th…