REVIEW 7 cited by
On the relation between perspective-neutral, algebraic, and effective quantum reference frames
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
On the relation between perspective-neutral, algebraic, and effective quantum reference frames
read the original abstract
The framework of internal quantum reference frames (QRFs) constitutes a universal toolset for dealing with symmetries in quantum theory and has led to new revelations in quantum gravity, gauge theories and foundational physics. Multiple approaches have emerged, sometimes differing in scope and the way symmetries are implemented, raising the question as to their relation. Here, we investigate the relation between three approaches to QRFs for gauge symmetries, namely the effective semiclassical, algebraic, and perspective-neutral (PN) approaches. Rather than constructing Hilbert spaces, as the PN approach, the effective approach is based on a quantum phase space parametrized by expectation values and fluctuations, while the emphasis of the algebraic approach is on the state space of complex linear functionals on a kinematical algebra. Nevertheless, external frame information is treated as gauge in all three formalisms, manifested in constraints on states and algebra. We show that these three approaches are, in fact, equivalent for ideal QRFs, distinguished by sharp orientations, which is the previous setting of the first two approaches. Our demonstration pertains to single constraints, including relativistic ones, and encompasses QRF changes. In particular, the QRF transformations of the PN framework agree semiclassically with those of the older effective approach, by which it was inspired. As a physical application, we explore the QRF covariance of uncertainties and fluctuations, which turn out to be frame-dependent. This is particularly well-suited for the effective and algebraic approaches, for which these quantities form a natural basis. Finally, we pave the way towards extending these two approaches to non-ideal QRFs by studying the projection and gauge-fixing operations of the Page-Wootters formalism, built into the PN framework, on algebraic states.
Forward citations
Cited by 7 Pith papers
-
Quantum reference frames beyond subsystems: a reconstruction and generalization of the perspective-neutral framework
Quantum reference frames need not be subsystems: covariant instruments suffice, recovering the perspective-neutral framework operationally and enabling labeling frames and exact interacting relational clocks.
-
Frame-Dependent Traces and the Third-Particle Paradox
The Third-Particle Paradox is not a contradiction: the authors characterize exactly which states allow consistent subsystem discarding in the perspective-neutral and quantum-information approaches.
-
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...
-
Universal $T$-matrices for quantum Poincar\'e groups: contractions and quantum reference frames
A new quantum deformation of the centrally extended Poincaré algebra is introduced whose universal T-matrix contracts to the Galilei T-matrix for quantum reference frames and appears as a central extension of the spac...
-
The Paradox of the Third Particle is classical
Even without quantum superpositions, changing the reference particle can make information that was locally readable from one perspective non-locally readable from another once a third particle is included.
-
Error Correction in Lattice Quantum Electrodynamics with Quantum Reference Frames
Lattice QED is established as a quantum error-correcting code beyond stabilizers, with explicit recovery operations constructed via quantum reference frames for gauge and fermionic sectors.
-
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 specif...
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.