186 citations · 1.1k across the 23 of their papers we have counts for
23 papers
Edge modes as reference frames and boundary actions from post-selection
Sylvain Carrozza, Philipp A. Hoehn
We introduce a general framework realizing edge modes in (classical) gauge field theory as dynamical reference frames, an often suggested interpretation that we make entirely expli…
Internal quantum reference frames for finite Abelian groups
Philipp A. Hoehn, Marius Krumm, Markus P. Mueller
Employing internal quantum systems as reference frames is a crucial concept in quantum gravity, gauge theories and quantum foundations whenever external relata are unavailable. In…
Quantum Relativity of Subsystems
Shadi Ali Ahmad, Thomas D. Galley, Philipp A. Hoehn +2
One of the most basic notions in physics is the partitioning of a system into subsystems, and the study of correlations among its parts. In this work, we explore these notions in t…
Equivalence of approaches to relational quantum dynamics in relativistic settings
Philipp A. Hoehn, Alexander R. H. Smith, Maximilian P. E. Lock
We have previously shown (arXiv:1912.00033) that three approaches to relational quantum dynamics -- relational Dirac observables, the Page-Wootters formalism and quantum deparametr…
The Trinity of Relational Quantum Dynamics
Philipp A. Hoehn, Alexander R. H. Smith, Maximilian P. E. Lock
The problem of time in quantum gravity calls for a relational solution. Using quantum reduction maps, we establish a previously unknown equivalence between three approaches to rela…
Switching quantum reference frames in the N-body problem and the absence of global relational perspectives
Augustin Vanrietvelde, Philipp A. Hoehn, Flaminia Giacomini
Given the importance of quantum reference frames (QRFs) to both quantum and gravitational physics, it is pertinent to develop a systematic method for switching between the descript…
Quantum theory from rules on information acquisition
Philipp A Hoehn
We summarise a recent reconstruction of the quantum theory of qubits from rules constraining an observer's acquisition of information about physical systems. This review of [arXiv:…
Is the local linearity of space-time inherited from the linearity of probabilities?
Markus P. Mueller, Sylvain Carrozza, Philipp A Hoehn
The appearance of linear spaces, describing physical quantities by vectors and tensors, is ubiquitous in all of physics, from classical mechanics to the modern notion of local Lore…
Can chaos be observed in quantum gravity?
Bianca Dittrich, Philipp A. Hoehn, Tim A. Koslowski +1
Full general relativity is almost certainly 'chaotic'. We argue that this entails a notion of nonintegrability: a generic general relativistic model, at least when coupled to cosmo…
Quantum theory from questions
Philipp A Hoehn, Christopher Wever
We reconstruct the explicit formalism of qubit quantum theory from elementary rules on an observer's information acquisition. Our approach is purely operational: we consider an obs…
An operational approach to spacetime symmetries: Lorentz transformations from quantum communication
Philipp A. Hoehn, Markus P. Mueller
In most approaches to fundamental physics, spacetime symmetries are postulated a priori and then explicitly implemented in the theory. This includes Lorentz covariance in quantum f…
Toolbox for reconstructing quantum theory from rules on information acquisition
Philipp A Hoehn
We develop an operational approach for reconstructing the quantum theory of qubit systems from elementary rules on information acquisition. The focus lies on an observer O interrog…
Canonical linearized Regge Calculus: counting lattice gravitons with Pachner moves
Philipp A. Hoehn
We afford a systematic and comprehensive account of the canonical dynamics of 4D Regge Calculus perturbatively expanded to linear order around a flat background. To this end, we co…
Classification of constraints and degrees of freedom for quadratic discrete actions
Philipp A. Hoehn
We provide a comprehensive classification of constraints and degrees of freedom for variational discrete systems governed by quadratic actions. This classification is based on the…
Quantization of systems with temporally varying discretization II: Local evolution moves
Philipp A Hoehn
Several quantum gravity approaches and field theory on an evolving lattice involve a discretization changing dynamics generated by evolution moves. Local evolution moves in variati…
Quantization of systems with temporally varying discretization I: Evolving Hilbert spaces
Philipp A. Hoehn
A temporally varying discretization often features in discrete gravitational systems and appears in lattice field theory models subject to a coarse graining or refining dynamics. T…
Effective relational dynamics of a nonintegrable cosmological model
Philipp A Hoehn, Emilia Kubalova, Artur Tsobanjan
We apply the effective approach to evaluating semiclassical relational dynamics to the closed Friedman--Robertson--Walker cosmological model filled with a minimally coupled massive…
Effective relational dynamics
Philipp A. Hoehn
We provide a synopsis of an effective approach to the problem of time in the semiclassical regime. The essential features of this new approach to evaluating relational quantum dyna…
Canonical formalism for simplicial gravity
Philipp A. Hoehn
We summarise a recently introduced general canonical formulation of discrete systems which is fully equivalent to the covariant formalism. This framework can handle varying phase s…
Canonical simplicial gravity
Bianca Dittrich, Philipp A Hoehn
A general canonical formalism for discrete systems is developed which can handle varying phase space dimensions and constraints. The central ingredient is Hamilton's principal func…
An effective approach to the problem of time
Martin Bojowald, Philipp A Hoehn, Artur Tsobanjan
A practical way to deal with the problem of time in quantum cosmology and quantum gravity is proposed. The main tool is effective equations, which mainly restrict explicit consider…
Encoding cosmological futures with conformal structures
Philipp A Hoehn, Susan M Scott
Quiescent cosmology and the Weyl curvature hypothesis possess a mathematical framework, namely the definition of an Isotropic Singularity, but only for the initial state of the uni…
From covariant to canonical formulations of discrete gravity
Bianca Dittrich, Philipp A Hoehn
Starting from an action for discretized gravity we derive a canonical formalism that exactly reproduces the dynamics and (broken) symmetries of the covariant formalism. For lineari…