Unimodular Hartle-Hawking wave packets and their probability interpretation

Alexandre, Bruno; Magueijo, João

doi:10.1103/physrevd.107.063501

Cited by 5 publications

(2 citation statements)

References 38 publications

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“…There is nothing exuberant about negative electric fields. This is forced upon us in the quantum theory [28][29][30] (see also [25]), should we require unitarity and starting from the connection representation. It is interesting that even classically we can find new solutions exhibiting what presumably is the peak of the wave packets moving from the a 2 < 0 to the a 2 > 0 region.…”

Section: Discussionmentioning

confidence: 99%

Overall signature of the metric and the cosmological constant

Alexandre,

Gielen,

Magueijo

2024

J. Cosmol. Astropart. Phys.

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We consider a little known aspect of signature change, where the overall sign of the metric is allowed to change, with physical implications. We show how, in different formulations of general relativity, this type of classical signature change across boundaries with a degenerate metric can be made consistent with a change in sign (and value) of the cosmological constant Λ. In particular, the separate “mostly plus” and “mostly minus” signature sectors of Lorentzian gravity are most naturally associated with different signs of Λ. We show how this general phenomenon allows for classical solutions where the open dS patch can arise from a portion of AdS space time. These can be interpreted as classical “imaginary space” extensions of the usual Lorentzian theory, with a 2 < 0.

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Section: Discussionmentioning

confidence: 99%

Overall signature of the metric and the cosmological constant

Alexandre,

Gielen,

Magueijo

2024

J. Cosmol. Astropart. Phys.

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“…These oscillatory characteristics are conventionally attributed to the interference of the incoming part of the wave packet with the outgoing part [26]. The same interpretation holds for the wave packet under consideration, giving us the familiar notion of quantum bounce [28][29][30], making a good case for the small value of the ordering parameter as the preferred choice. On the other hand, the behavior of the wave packet for a broadly peaked energy distribution is highly counterintuitive, and the origin and interpretation of the oscillatory features at late times are a mystery at this juncture.…”

Section: Quantum Modelmentioning

confidence: 95%

Operator ordering ambiguity in observables of quantum cosmology

Sahota

Lochan

2023

The Sixteenth Marcel Grossmann Meeting

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Sharply peaked quantum states are conjectured to be conducive to the notion of a quantumcorrected spacetime. For a flat-FLRW model with perfect fluid, a generalized ordering scheme is considered for the Hamiltonian, and we study the implication of different ordering choices on the observables. We demonstrate that the operator ordering ambiguity leaves no imprint in the case of sharply peaked states, leading to a consistent semiclassical picture for a quantum-corrected spacetime.

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Mach's principle and dark matter

Magueijo

2024

Physics Letters B

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Unimodular Hartle-Hawking wave packets and their probability interpretation

Cited by 5 publications

References 38 publications

Overall signature of the metric and the cosmological constant

Overall signature of the metric and the cosmological constant

Operator ordering ambiguity in observables of quantum cosmology

Mach's principle and dark matter

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