REVIEW 4 cited by
Effective relational dynamics of a nonintegrable cosmological model
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
read the original abstract
We apply the effective approach to evaluating semiclassical relational dynamics to the closed Friedman--Robertson--Walker cosmological model filled with a minimally coupled massive scalar field. This model is interesting for studying relational dynamics in a more general setting because (i) it features a nontrivial coupling of the relational clock to the evolving degrees of freedom, (ii) no temporally global clock variable exists, and (iii) it is nonintegrable which is typical for generic dynamical systems. The effective approach is especially well geared for addressing the concept of relational evolution in this context, since it enables one to switch between different clocks and yields a consistent (temporally) local time evolution with transient observables so long as semiclassicality holds. We provide evidence that relational evolution in this model universe, while possible for sufficiently semiclassical states, generically breaks down in the region of maximal expansion. This is rooted in a defocusing of classical trajectories, which leads to a rapid spreading of states that are initially sharply peaked and to a mixing of internal time directions in this region. These results are qualitatively compared to previous work on this model, revisiting conceptual issues that have been raised earlier in the literature.
Forward citations
Cited by 4 Pith papers
-
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.
-
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.
-
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.