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Braneworld gravity
 Living Rev. Rel
"... The observable universe could be a 1 + 3surface (the “brane”) embedded in a 1 + 3 + ddimensional spacetime (the “bulk”), with Standard Model particles and fields trapped on the brane while gravity is free to access the bulk. At least one of the d extra spatial dimensions could be very large relati ..."
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Cited by 37 (0 self)
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The observable universe could be a 1 + 3surface (the “brane”) embedded in a 1 + 3 + ddimensional spacetime (the “bulk”), with Standard Model particles and fields trapped on the brane while gravity is free to access the bulk. At least one of the d extra spatial dimensions could be very large relative to the Planck scale, which lowers the fundamental gravity scale, possibly even down to the electroweak ( ∼ TeV) level. This revolutionary picture arises in the framework of recent developments in M theory. The 1+10dimensional M theory encompasses the known 1 + 9dimensional superstring theories, and is widely considered to be a promising potential route to quantum gravity. General relativity cannot describe gravity at high enough energies and must be replaced by a quantum gravity theory, picking up significant corrections as the fundamental energy scale is approached. At low energies, gravity is localized at the brane and general relativity is recovered, but at high energies gravity “leaks ” into the bulk, behaving in a truly higherdimensional way. This introduces significant changes to gravitational dynamics and perturbations, with interesting and potentially testable implications for highenergy astrophysics, black holes, and cosmology. Braneworld models offer a phenomenological way to test some of the novel predictions and corrections to general relativity that are implied by M theory. This review discusses the geometry, dynamics and perturbations of simple braneworld models for cosmology and astrophysics, mainly focusing on warped 5dimensional braneworlds based on the Randall–Sundrum models. c©Max Planck Society and the authors. Further information on copyright is given at
Dynamics of intersecting brane systems
, 903
"... Preprint typeset in JHEP style HYPER VERSION KUTP 030 ..."
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Cited by 7 (5 self)
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Preprint typeset in JHEP style HYPER VERSION KUTP 030
The Cosmological Slingshot Scenario: A Stringy Early Times Universe
, 2008
"... Abstract. A cosmological model for the early time Universe is proposed. In this model, the Universe is a wandering brane moving in a warped throat of a CalabiYau space. A nonzero angular momentum induces a turning point in the brane trajectory, and leads to a bouncing cosmology as experienced by a ..."
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Abstract. A cosmological model for the early time Universe is proposed. In this model, the Universe is a wandering brane moving in a warped throat of a CalabiYau space. A nonzero angular momentum induces a turning point in the brane trajectory, and leads to a bouncing cosmology as experienced by an observer living on the brane. The Universe undergoes a decelerated contraction followed by an accelerating expansion and no bigbang singularity. Although the number of efolds of accelerated motion is low (less than 2), standard cosmological problems are not present in our model thanks to the absence of an initial singularity and the violation of energy conditions of mirage matter at high energies. Density perturbations are also calculated in our model and we find a slightly red spectral index with negligible tensorial perturbations in compatibility with WMAP data. The Cosmological Slingshot Scenario: A Stringy Early Times Universe 2 1.
CPHTRR069.0906 hepth/0610255 Warped Supersymmetry Breaking
, 2007
"... Abstract: We address the size of supersymmetrybreaking effects within string theory settings where the observable sector resides deep within a strongly warped region, with supersymmetry breaking not necessarily localized in that region. Our particular interest is in how the supersymmetrybreaking s ..."
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Abstract: We address the size of supersymmetrybreaking effects within string theory settings where the observable sector resides deep within a strongly warped region, with supersymmetry breaking not necessarily localized in that region. Our particular interest is in how the supersymmetrybreaking scale seen by the observable sector depends on this warping. We focus concretely on type IIB flux compactifications and obtain this dependence in two ways: by computing within the microscopic string theory supersymmetrybreaking masses in Dpbrane supermultiplets; and by investigating how warping gets encoded into masses within the lowenergy 4D effective theory. We identify two different ways to identify ‘the ’ 4D gravitino in such systems – the state whose supersymmetry is the least broken, and the state whose couplings are the most similar to the 4D graviton’s – and argue that these need not select the same state in strongly warped settings. We formulate the conditions required for the existence of a description in terms of a 4D SUGRA formulation, or in terms of 4D SUGRA together with softbreaking terms, and describe in particular situations where neither exist for some nonsupersymmetric compactifications. We suggest that some effects of warping are captured by a linear A dependence in the Kähler potential. We outline some implications of our results for the KKLT scenario of moduli stabilization with broken SUSY. Contents