Mixmaster dynamics in the dust time gauge

Ali, Masooma; Husain, Viqar

doi:10.1103/physrevd.96.044032

Cited by 6 publications

(5 citation statements)

References 33 publications

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“…(An exception to this is an ekpyrotic field with an equation of state greater than 1, which will dominate over anisotropies, but in this case the space-time will be driven to the FLRW solution [57], and then there is no need to include anistropies.) Nonetheless, it is possible to include other types of matter fields, for example the effect of a dust field is studied in [58].…”

Section: Classical Theorymentioning

confidence: 99%

“…Note also that if the spatial manifold is non-compact, then it is necessary to restrict integrals to a fiducial cell, with coordinate volume 3 o , but the dynamics of the space-time are independent of the choice of the fiducial cell. possible to include other types of matter fields, for example the effect of a dust field is studied in [58].…”

Section: Classical Theorymentioning

confidence: 99%

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The loop quantum cosmology bounce as a Kasner transition

Wilson-Ewing

2018

Class. Quantum Grav.

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For the Bianchi type I space-time (vacuum or with a massless scalar field), the loop quantum cosmology bounce can be viewed as a rapid transition between two classical solutions, with a simple transformation rule relating the Kasner exponents of the two epochs. This transformation rule can be extended to other Bianchi space-times under the assumption that during the loop quantum cosmology bounce the contribution of the spatial curvature to the Hamiltonian constraint is negligible compared to the kinetic terms. For the vacuum Bianchi type IX space-time there are transformation rules for how each of the parameters characterizing the Kasner epochs change during the bounce. This provides a quantum gravity extension to the Mixmaster dynamics of general relativity, and may have interesting implications for the Belinski-Khalatnikov-Lifshitz conjecture.

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Section: Classical Theorymentioning

confidence: 99%

Section: Classical Theorymentioning

confidence: 99%

The loop quantum cosmology bounce as a Kasner transition

Wilson-Ewing

2018

Class. Quantum Grav.

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“…To see this, note that the relations (37) and (38) hold in full generality, including around the recollapse point. Therefore, solving for δ ± either side of the recollapse determines the quasi-Kasner exponents k ± i .…”

Section: Generalizations Beyond Single-bounce Cosmologymentioning

confidence: 99%

“…The Heckmann-Schücking solution describes a Bianchi I universe filled with a stiff fluid (ω = 1) and dust (ω = 0), the directional scale factors evolve as [36][37][38]…”

Section: Heckmann-schücking Solutionmentioning

confidence: 99%

A generalized Kasner transition for bouncing Bianchi I models in modified gravity theories

Cesare

Wilson-Ewing

2019

J. Cosmol. Astropart. Phys.

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We derive transition rules for Kasner exponents in bouncing Bianchi I models with generic perfect fluid matter fields for a broad class of modified gravity theories where cosmological singularities are resolved and replaced by a non-singular bounce. This is a generalization of results obtained previously in limiting curvature mimetic gravity and loop quantum cosmology. A geometric interpretation is provided for the transition rule as a linear map in the Kasner plane. We show that the general evolution of anisotropies in a Bianchi I universe-including during the bounce phase-is equivalent to the motion of a point particle on a sphere, where the sphere is the one-point compactification of the Kasner plane. In addition, we study the evolution of anisotropies in a large family of bouncing Bianchi I space-times. We also present a novel explicit solution to the Einstein equations for a Bianchi I universe with ekpyrotic matter with a constant equation of state ω = 3. *

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“…These include studying larger classes of initial data, and going beyond FRW to Bianchi cosmologies. The latter have been studied classically in dust time gauge [24], and would provide a richer arena for studying entanglement between between different scale factors, as well as with scalar fields. Of most interest would be the gravity-dustscalar theory in spherical symmetry since this contains black hole This is of obvious relevance for black hole entropy and the "information loss problem;" that quantum gravity causes matter-gravity entanglement in such systems has been shown but not computed [25].…”

Section: Model and Quantization Let Us First Recall The Classical The...mentioning

confidence: 99%

Matter-Geometry entanglement in quantum cosmology

Husain,

Singh

2019

Preprint

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We present a study of the evolution of entanglement entropy of matter and geometry in quantum cosmology. For a variety of initial quantum states of the Universe, and with evolution defined with respect to a relational time, we show numerically that (i) entanglement entropy increases rapidly at very early times, and subsequently saturates to a constant non-zero value, and (ii) that the saturation value of this entropy is a linear function of the energy associated to the quantum state: S ψ ent = γ Ĥ ψ . These results suggest a remnant of quantum entanglement in the macroscopic Universe from the era of the Big Bang, independent of the initial state, and a "First Law" associated with matter-gravity entanglement entropy in quantum gravity.

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Mixmaster dynamics in the dust time gauge

Cited by 6 publications

References 33 publications

The loop quantum cosmology bounce as a Kasner transition

The loop quantum cosmology bounce as a Kasner transition

A generalized Kasner transition for bouncing Bianchi I models in modified gravity theories

Matter-Geometry entanglement in quantum cosmology

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