Effects of a scalar field on the thermodynamics of interuniversal entanglement

Garay, Iñaki; Robles-Pérez, Salvador

doi:10.1142/s0218271814500436

Cited by 17 publications

(34 citation statements)

References 72 publications

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“…so the minisuperspace corresponds to a Minkowski like space but in general the minisupermetric is a curved minisuperspace (see, for instance, Ref. [25,69]).…”

Section: A Third Quantization Formalismmentioning

confidence: 99%

Quantum cosmology of a conformal multiverse

Robles-Pérez

2017

Phys. Rev. D

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This paper studies the cosmology of a homogeneous and isotropic spacetime endorsed with a conformally coupled massless scalar field. We find six different solutions of the Friedmann equation that represent six different types of universes, and all of them are periodically distributed along the complex time axis. From a classical point of view, they are then isolated, separated by Euclidean regions that represent quantum mechanical barriers. Quantum mechanically, however, there is a nonzero probability for the state of the universes to tunnel out through a Euclidean instanton and suffer a sudden transition to another state of the spacetime. We compute the probability of transition for this and other nonlocal processes like the creation of universes in entangled pairs and, generally speaking, in multipartite entangled states. We obtain the quantum state of a single universe within the formalism of the Wheeler-DeWitt equation and give the semiclassical state of the universes that describes the quantum mechanics of a scalar field propagating in a de Sitter background spacetime. We show that the superposition principle of the quantum mechanics of matter fields alone is an emergent feature of the semiclassical description of the universe that is not valid, for instance, in the spacetime foam. We use the third quantization formalism to describe the creation of an entangled pair of universes with opposite signs of the momentum conjugated to the scale factor. Each universe of the entangled pair represents an expanding spacetime in terms of the Wentzel-Kramers-Brillouin (WKB) time experienced by internal observers in their particle physics experiments. We compute the effective value of the Friedmann equation of the background spacetime of the two entangled universes, and thus, the effect that the entanglement would have in their expansion rates. We analyze as well the effects of the interuniversal entanglement in the properties of the scalar fields that propagate in each spacetime of the entangled pair. We find that the largest modes of the scalar field are unaware of the entanglement between the universes, but the effects can be significant for the lowest modes, allowing us to compute, in principle, detailed observational imprints of the multiverse in the properties of a single universe like ours.

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“…so the minisuperspace corresponds to a Minkowski like space but in general the minisupermetric is a curved minisuperspace (see, for instance, Ref. [25,69]).…”

Section: A Third Quantization Formalismmentioning

confidence: 99%

Quantum cosmology of a conformal multiverse

Robles-Pérez

2017

Phys. Rev. D

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“…This is similar to the case of a general curved space-time, where a non-well-defined notion of time makes it impossible to give a proper definition of a particle. However, for homogeneous and isotropic space-times the scale factor can formally be seen as the time-like variable of the minisuperspace, which can also be inferred from the Lorentzian signature of the minisupermetric of the minisuperspace [14,33,40,41]. In those cases the formalism simplifies and a quantum field procedure can be applied to the minisuperspace much in the same way as it is done in a usual quantum field theory.…”

Section: Introductionmentioning

confidence: 99%

The interacting multiverse and its effect on the cosmic microwave background

Bouhmadi-López

Kraemer

Morais

et al. 2019

J. Cosmol. Astropart. Phys.

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We study a toy model of a multiverse consisting of canonically quantized universes that interact with each other on a quantum level based on a field-theoretical formulation of the Wheeler-DeWitt equation. This interaction leads to the appearance of a pre-inflationary phase in the evolution of the individual universes. We analyze scalar perturbations within the model and calculate the influence of the pre-inflationary phase onto the power spectrum of these perturbations. The result is that there is a suppression of power on large scales, which can describe well the Planck 2018 data for the cosmic microwave background anisotropies and could thus indicate a possible solution to the observed quadrupole discrepancy.

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“…We shall see in the next section that in terms of the same time variable, one of the two terms in (24), say the branch with e −iS , describes an expanding universe, and the branch with e iS describes a contracting universe. It means that the result of imposing the no-boundary condition on the quantum state of the universe is that it is given by the linear combination of two states: one representing an expanding universe and one representing a contracting universe.…”

Section: Boundary Conditionsmentioning

confidence: 99%

Quantum Cosmology with Third Quantisation

Robles-Pérez

2021

Universe

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We reviewed the canonical quantisation of the geometry of the spacetime in the cases of a simply and a non-simply connected manifold. In the former, we analysed the information contained in the solutions of the Wheeler–DeWitt equation and showed their interpretation in terms of the customary boundary conditions that are typically imposed on the semiclassical wave functions. In particular, we reviewed three different paradigms for the quantum creation of a homogeneous and isotropic universe. For the quantisation of a non-simply connected manifold, the best framework is the third quantisation formalism, in which the wave function of the universe is seen as a field that propagates in the space of Riemannian 3-geometries, which turns out to be isomorphic to a (part of a) 1 + 5 Minkowski spacetime. Thus, the quantisation of the wave function follows the customary formalism of a quantum field theory. A general review of the formalism is given, and the creation of the universes is analysed, including their initial expansion and the appearance of matter after inflation. These features are presented in more detail in the case of a homogeneous and isotropic universe. The main conclusion in both cases is that the most natural way in which the universes should be created is in entangled universe–antiuniverse pairs.

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Effects of a scalar field on the thermodynamics of interuniversal entanglement

Cited by 17 publications

References 72 publications

Quantum cosmology of a conformal multiverse

Quantum cosmology of a conformal multiverse

The interacting multiverse and its effect on the cosmic microwave background

Quantum Cosmology with Third Quantisation

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