2,525 research outputs found
Spacetime Equals Entanglement
We study the Hilbert space structure of classical spacetimes under the
assumption that entanglement in holographic theories determines semiclassical
geometry. We show that this simple assumption has profound implications; for
example, a superposition of classical spacetimes may lead to another classical
spacetime. Despite its unconventional nature, this picture admits the standard
interpretation of superpositions of well-defined semiclassical spacetimes in
the limit that the number of holographic degrees of freedom becomes large. We
illustrate these ideas using a model for the holographic theory of cosmological
spacetimes.Comment: 6 pages, 2 figures; v2: remarks on time evolution revised, v3:
matches published versio
Entanglement in a multiverse with no common space-time
Inter-universal entanglement may even exist in a multiverse in which there is
no common space-time among the universes. In particular, the entanglement
between the expanding and contracting branches of the universe might have
observable consequences in the dynamical and thermodynamical properties of one
single branch, making therefore testable the whole multiverse proposal, at
least in principle.Comment: 4 pages. Prepared for the proceedings of the Multiverse and
Fundamental Cosmology Meeting (Multicosmofun'12
Cosmological quantum entanglement
We review recent literature on the connection between quantum entanglement
and cosmology, with an emphasis on the context of expanding universes. We
discuss recent theoretical results reporting on the production of entanglement
in quantum fields due to the expansion of the underlying spacetime. We explore
how these results are affected by the statistics of the field (bosonic or
fermionic), the type of expansion (de Sitter or asymptotically stationary), and
the coupling to spacetime curvature (conformal or minimal). We then consider
the extraction of entanglement from a quantum field by coupling to local
detectors and how this procedure can be used to distinguish curvature from
heating by their entanglement signature. We review the role played by quantum
fluctuations in the early universe in nucleating the formation of galaxies and
other cosmic structures through their conversion into classical density
anisotropies during and after inflation. We report on current literature
attempting to account for this transition in a rigorous way and discuss the
importance of entanglement and decoherence in this process. We conclude with
some prospects for further theoretical and experimental research in this area.
These include extensions of current theoretical efforts, possible future
observational pursuits, and experimental analogues that emulate these cosmic
effects in a laboratory setting.Comment: 23 pages, 2 figures. v2 Added journal reference and minor changes to
match the published versio
Emergence of multiverse in third quantized varying constants cosmologies
Although the standard cosmological model explains most of the observed
phenomena it still struggles with the problem of initial singularity. An
interesting scenario in which the problem of the initial singularity is somehow
circumvented was proposed in the context of string theory where the canonical
quantisation procedure was additionally applied. A similar effect can be
achieved in the context of the canonically quantized theory with varying speed
of light and varying gravitational constant where both quantities are
represented by non-minimally coupled scalar fields. Such theory contains both
the pre-big-bang contracting phase and the post-big-bang expanding phase and
predicts non-vanishing probability of the transition from the former to the
latter phase. In this paper we quantize such a theory once again by applying
the third quantization scheme and show that the resulting theory contains
scenario in which the whole multiverse is created from nothing. The generated
family of the universes is described by the Bose-Einstein distribution.Comment: 6 pages, 2 figure
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