REVIEW 13 cited by
Edge modes as reference frames and boundary actions from post-selection
Not yet reviewed by Pith; the record is open.
This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.
SPECIMEN: schema-true, not a live event
T0 review · schema-true
One-sentence machine reading of the paper's core claim.
pith:XXXXXXXX · record.json · timestamp
Signed reviews
abstract
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 explicit. We focus on a bounded region $M$ with a co-dimension one time-like boundary $\Gamma$, which we embed in a global spacetime. Taking as input a variational principle at the global level, we develop a systematic formalism inducing consistent variational principles (and in particular, boundary actions) for the subregion $M$. This relies on a post-selection procedure on $\Gamma$, which isolates the subsector of the global theory compatible with a general choice of gauge-invariant boundary conditions for the dynamics in $M$. Crucially, the latter relate the configuration fields on $\Gamma$ to a dynamical frame field carrying information about the spacetime complement of $M$; as such, they may be equivalently interpreted as frame-dressed or relational observables. Generically, the external frame field keeps an imprint on the ensuing dynamics for subregion $M$, where it materializes itself as a local field on the time-like boundary $\Gamma$; in other words, an edge mode. We identify boundary symmetries as frame reorientations and show that they divide into three types, depending on the boundary conditions, that affect the physical status of the edge modes. Our construction relies on the covariant phase space formalism, and is in principle applicable to any gauge (field) theory. We illustrate it on three standard examples: Maxwell, Abelian Chern-Simons and non-Abelian Yang-Mills theories. In complement, we also analyze a mechanical toy-model to connect our work with recent efforts on (quantum) reference frames.
Forward citations
Cited by 13 Pith papers
-
Relational path integral, effective actions and quantum frame covariance in gravity
The gravitational path integral is reformulated with dynamical reference frames, producing gauge-invariant correlators, frame-dependent vacua, and effective actions, with sharpness of events becoming frame-relative.
-
How many degrees of freedom describe a quantum N-particle state?
For closed quantum N-particle systems all 3N canonical degrees of freedom are physical; the frame degrees of freedom that relational models discard reappear as non-Heisenberg terms in generalised uncertainty relations...
-
Semi-local observables, edge modes and quantum reference frames in quantum electromagnetism: an algebraic approach
Electromagnetic edge modes on bounded spacetimes with corners are treated as quantum reference frames for large gauge transformations via a state-independent C*-algebraic relativisation map, with superselection sector...
-
Relational entanglement entropies and quantum reference frames in gauge theories
Quantum reference frames built from Wilson lines give lattice gauge theories gauge-invariant subsystem factorizations and a hierarchy of relational entanglement entropies.
-
Dressed Subsystems in Classical Gravity
Internally dressed subsystems, whose boundaries are located by fields within the region, are exactly those whose observables close under Poisson brackets in generally covariant theories.
-
Relational Observables in Group Field Theory
POVM-based conditioning on scalar-field quantum reference frames defines relational observables in group field theory that match prior number and volume results on coherent states.
-
Soft edges: the many links between soft and edge modes
In Maxwell theory, asymptotically charged edge modes (soft edges) pull asymptotic symmetries and soft data into finite subregions, giving finite-distance corner charges without an infinite-volume limit.
-
On the relation between perspective-neutral, algebraic, and effective quantum reference frames
For ideal quantum reference frames with a single constraint, the perspective-neutral, algebraic, and effective semiclassical approaches describe the same physics and the same frame-switching rules.
-
Crossed products and quantum reference frames: on the observer-dependence of gravitational entropy
Gravitational subregion entropy is observer-dependent: different quantum clocks produce different von Neumann algebras and different entropy functionals for the same global state.
-
Dynamical edge modes in Maxwell theory from a BRST perspective, with an application to the Casimir energy
DEM boundary conditions on two parallel plates yield the same Casimir energy as perfectly conducting plates, after restoring BRST invariance with boundary ghost fields.
-
Linearization (in)stabilities and crossed products
Second-order Taub charge constraints are justified as linearization stability conditions in spatially closed spacetimes, while in boundary or no-isometry cases the justification is weaker and depends on interest in se...
-
Specifying the operational meaning of quantum reference frames
Position-superposed labs define quantum reference frames operationally, differ from Wigner's-friend observers, and can broadcast outcomes without decohering their position superposition.
-
What can we do in a symmetry-constrained perspective? The importance of the total charge's status in quantum reference frame frameworks
A two-observer Z2 toy model is used to argue that internal observers can access the total charge, favoring weak over strong symmetry in quantum reference frame frameworks.
Discussion (0). Continue with ORCID to comment.