Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 0707.4679

On the Transfer of Adiabatic Fluctuations through a Nonsingular Cosmological Bounce

Stephon Alexander·Tirthabir Biswas·Robert H. Brandenberger
View original source ↗Read source document ↗Export metadata ↓

Abstract

We study the transfer of cosmological perturbations through a nonsingular cosmological bounce in a special model in which the parameters of the bounce and the equation of state of matter are chosen such as to allow for an exact calculation of the evolution of the fluctuations. We find that the growing mode of the metric fluctuations in the contracting phase goes over into the growing mode in the expanding phase, a result which is different from what is obtained in analyses in which fluctuations are matched at a singular hypersurface. Consequences for Ekpyrotic cosmology are discussed in a limit when the equation of state of a fluid becomes large.

Explore related subjects

hep-thastro-phgr-qchep-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Stephon Alexander, Tirthabir Biswas, Robert H. Brandenberger. 2008-07-30. On the Transfer of Adiabatic Fluctuations through a Nonsingular Cosmological Bounce. https://arxiv.org/abs/0707.4679

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

A Concise Course in String Theory

These lecture notes offer a concise introduction to string theory, based on a one-semester graduate course taught at Fudan University, and develop the subject from the string sigma model action to the AdS/CFT correspondence. The exposition is deliberately compact, and is addressed to graduate students who seek a coherent overview of the foundations of the subject rather than an exhaustive treatment.

hep-th↗
arXiv2026

One loop aspects of Coleman de Luccia instantons at small backreaction

We discuss the Euclidean path integral around Coleman de Luccia instantons. We compute their contribution at the one-loop level, at leading order in the small backreaction limit. At this level of approximation, their contribution factorizes into a pure gravity and a pure matter contribution. In deriving this result, we also clarify what happens to some zero mode contributions to the path integral, once the symmetry responsible for them is broken. With these results established, we propose a formula for the decay rate of the false vacuum in terms of gravitational path integrals, and we show that our definition matches the usual quantum field theory result as $G_{N}\rightarrow0$. Lastly, we propose a prescription to study how the phase of the gravity+matter path integral changes as we change the parameters of the theory.

hep-th↗
arXiv2026

Special Kähler geometries of $\mathcal{N}=4$ superYang-Mills

The low energy effective theory on the moduli space of vacua of 4d superYang-Mills (sYM) theory defines a special Kähler geometry. For simple sYM gauge algebras, $\mathfrak{g}$, we classify all compatible special Kähler structures by showing that they are in one-to-one correspondence with certain equivalence classes of integral symplectic representations of the Weyl group of $\mathfrak{g}$. We further demonstrate that, for principal Dirac pairing, these equivalence classes are in one-to-one correspondence with the S-duality orbits of the global structures of the corresponding $\mathfrak{g}$ sYM gauge theory, after a mistake in the field theory literature is corrected. This provides a low-energy test of S-duality. We also discuss twisted product geometries made from factors with special Kähler structures with non-principal Dirac pairings.

hep-th↗