Results 21 to 30 of about 1,328,728 (267)
Holographic principle and string cosmology [PDF]
Classical and Quantum Gravity, 1999 String cosmology is revisited from cosmological viewpoint of holographic principle put forward by `t Hooft, and by Fischler and Susskind. It is shown that the holography requires existence of a `graceful exit' mechanism, which renders the Universe nonsingular by connecting pre- and post-big bang phases smoothly.
Bak, Dongsu, Rey, Soo-Jong
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EQUIVALENCE PRINCIPLE IN COSMOLOGY [PDF]
, 2014 We analyse the Einstein equivalence principle (EEP) for a Hubble observer in Friedmann-Lemaitre-Robertson-Walker spacetime. We show that the affine structure of light cone in the FLRW spacetime should be treated locally in terms of the optical metric which is not reduced to the Minkowski metric due to the non-uniform parametrization of the local ...
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Comments on the cosmological constant in generalized uncertainty models
Frontiers in Astronomy and Space Sciences, 2022 The existence of a small, non-zero cosmological constant is one of the major puzzles in fundamental physics. Naively, quantum field theory arguments would imply a cosmological constant which is up to 10,120 times larger than the observed one.
Michael Bishop +3 more
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A Dynamic Dark Information Energy Consistent with Planck Data
Entropy, 2014 The 2013 cosmology results from the European Space Agency Planck spacecraft provide new limits to the dark energy equation of state parameter. Here we show that Holographic Dark Information Energy (HDIE), a dynamic dark energy model, achieves an optimal ...
Michael Paul Gough
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, 2021 This Bachelor of Science thesis details the mathematical foundations of cosmology. It reviews the fundamental concepts of differential and Riemannian geometry, including manifolds, one-forms, tensors, connections, and the Levi-Civita connection. The thesis then applies these concepts to cosmology by examining spacetime manifolds, the Cosmological ...
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Anthropic reasoning in multiverse cosmology and string theory [PDF]
, 2005 Anthropic arguments in multiverse cosmology and string theory rely on the weak anthropic principle (WAP). We show that the principle, though ultimately a tautology, is nevertheless ambiguous.
Weinstein, Steven, Steven Weinstein
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The principle of least action and clustering in cosmology [PDF]
Monthly Notices of the Royal Astronomical Society, 1994 A scheme is developed which enables one to trace backwards in time the cosmic density and velocity fields, and to determine accurately the current-epoch velocity field from the current-epoch density field, or vice versa. The scheme implements the idea of Giavalisco \etal\ (1993) that the principle of least action should be used to formulate ...
Susperregi, M, Binney, J
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Cosmological hyperfluids, torsion and non-metricity
European Physical Journal C: Particles and Fields, 2020 We develop a novel model for cosmological hyperfluids, that is fluids with intrinsic hypermomentum that induce spacetime torsion and non-metricity. Imposing the cosmological principle to metric-affine spaces, we present the most general covariant form of
Damianos Iosifidis
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Creation of wormholes during the cosmological bounce
European Physical Journal C: Particles and Fields, 2023 In this work we demonstrate that wormholes can in principle be naturally created during the cosmological bounce without the need for the exotic matter or any kind of additional modifications of the gravitational sector, apart from the one enabling the ...
Petar Pavlović, Marko Sossich
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Infrared (in)sensitivity of relativistic effects in cosmological observable statistics
Physics Letters B, 2023 The relativistic effects in cosmological observables contain critical information about the initial conditions and gravity on large scales. Compared to the matter density fluctuation, some of these relativistic contributions scale with negative powers of
Ermis Mitsou, Jaiyul Yoo, Matteo Magi
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