Cosmological Surprises from Braneworld models of Dark Energy

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dc.creatorSahni, Varun
dc.date2005-02-02
dc.date2005-04-25
dc.date.accessioned2026-07-07T06:21:45Z
dc.date.available2026-07-07T06:21:45Z
dc.descriptionProperties of Braneworld models of dark energy are reviewed. Braneworld models admit the following interesting possibilities: (i) The effective equation of state can be w < -1 as well as w > -1. In the former case the expansion of the universe is well behaved at all times and the universe does not run into a future `Big Rip' singularity which is usually encountered by Phantom models. (ii) For a class of Braneworld models the acceleration of the universe can be a transient phenomenon. In this case the current acceleration of the universe is sandwiched between two matter dominated epochs. Such a braneworld does not have a horizon in contrast to LCDM and most Quintessence models. (iii) For a specific set of parameter values the universe can either originate from, or end its existence in a Quiescent singularity, at which the density, pressure and Hubble parameter remain finite, while the deceleration parameter and all invariants of the Riemann tensor diverge to infinity within a finite interval of cosmic time. (iv) Braneworld models of dark energy can loiter at high redshifts: $6 \lleq z \lleq 40$. The Hubble parameter decreasesduring the loitering epoch relative to its value in LCDM. As a result the age of the universe at loitering dramatically increases and this is expected to boost the formation of high redshift gravitationally bound systems such as $10^9 M_\odot$ black holes at $z \sim 6$ and lower-mass black holes and/or Population III stars at $z > 10$, whose existence could be problematic within the LCDM scenario. (v) Braneworld models with a time-like extra dimension bounce at early times thereby avoiding the initial `Big Bang singularity'. (vi) Both Inflation and Dark Energy can be successfully unified within a single scheme (Quintessential Inflation).
dc.descriptionlatex 21 pages, 11 figures; Invited talk at the 14th international workshop on General relativity and Gravitation, Yukawa Institute for Theoretical Physics, Nov 29-Dec 3, 2004, Kyoto, Japan. An important comment added in section 6; additional references
dc.identifierhttps://arxiv.org/abs/astro-ph/0502032
dc.identifierhttp://arxiv.org/abs/astro-ph/0502032
dc.identifierProceedings of the 14th Workshop on General relativity and Gravitation (JGRG14), Kyoto University, Japan 29 November - 3 December, 2004. Edited by W. Hikida, M. Sasaki, T. Tanaka and T. Nakamura; p 95 - 115.
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/95703
dc.subjectAstrophysics
dc.subjectGeneral Relativity and Quantum Cosmology
dc.subjectHigh Energy Physics - Phenomenology
dc.subjectHigh Energy Physics - Theory
dc.titleCosmological Surprises from Braneworld models of Dark Energy
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