Search results for "Non-standard cosmology"

showing 3 items of 3 documents

Dark energy cosmologies for codimension-two branes

2005

A six-dimensional universe with two branes in the "football-shaped" geometry leads to an almost realistic cosmology. We describe a family of exact solutions with time dependent characteristic size of internal space. After a short inflationary period the late cosmology is either of quintessence type or turns to a radiation dominated Friedmann universe where the cosmological constant appears as a free integration constant of the solution. The radiation dominated universe with relativistic fermions is analyzed in detail, including its dimensional reduction.

High Energy Physics - TheoryPhysicsNuclear and High Energy PhysicsBig RipFOS: Physical sciencesNon-standard cosmologyLambda-CDM modelCosmological constantAstrophysics::Cosmology and Extragalactic AstrophysicsMetric expansion of spaceTheoretical physicsGeneral Relativity and Quantum CosmologyClassical mechanicsHigh Energy Physics - Theory (hep-th)De Sitter universeQuantum cosmologyScale factor (cosmology)
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The cosmological constant problem in codimension-two brane models

2005

We discuss the possibility of a dynamical solution to the cosmological constant problem in the contaxt of six-dimensional Einstein-Maxwell theory. A definite answer requires an understanding of the full bulk cosmology in the early universe, in which the bulk has time-dependent size and shape. We comment on the special properties of codimension two as compared to higher codimensions.

High Energy Physics - TheoryPhysicsNuclear and High Energy PhysicsFOS: Physical sciencesNon-standard cosmologyCosmological constantMetric expansion of spaceGeneral Relativity and Quantum Cosmologysymbols.namesakeTheoretical physicsClassical mechanicsHigh Energy Physics - Theory (hep-th)De Sitter universeFriedmann–Lemaître–Robertson–Walker metricBrane cosmologysymbolsBraneCosmological constant problemPhysics Letters B
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Little Rip, ΛCDM and singular dark energy cosmology from Born–Infeld-f(R) gravity

2014

Abstract We study late-time cosmic accelerating dynamics from Born–Infeld- f ( R ) gravity in a simplified conformal approach. We find that a variety of cosmic effects such as Little Rip, ΛCDM universe and dark energy cosmology with finite-time future singularities may occur. Unlike the convenient Born–Infeld gravity where in the absence of matter only de Sitter expansion may emerge, apparently any FRW cosmology maybe reconstructed from this conformal version of the Born–Infeld- f ( R ) theory. Despite the fact that the explicit form of f ( R ) is fixed by the conformal ansatz, the relation between the two metrics in this approach may be changed so as to bring out any desired FRW cosmology.

PhysicsNuclear and High Energy Physicsmedia_common.quotation_subjectNon-standard cosmologyAstrophysics::Cosmology and Extragalactic AstrophysicsCosmologyUniverseGeneral Relativity and Quantum CosmologyClassical mechanicsDe Sitter universeBorn–Infeld modelDark energyf(R) gravityDark fluidmedia_commonMathematical physicsPhysics Letters B
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