Related papers: Cosmological Phase Transitions and Radius Stabiliz…
It has been argued that the Randall-Sundrum (RS) phase transition rate is suppressed when the holographic theory corresponds to a large $N$ Yang-Mills and when the stabilizing field has a small mass. Here we argue that self-interactions can…
The presence of additional compact dimensions in cosmological models is studied in the context of modified teleparallel theories of gravity. We focus the analysis on eleven dimensional spacetimes, where the seven dimensional extra…
We consider new cosmological solutions with a collapsing, an intermediate and an expanding phase. The boundary between the expanding (collapsing) phase and the intermediate phase is seen by comoving observers as a cosmological past (future)…
In Kaluza-Klein compactifications, some symmetries of the higher dimensional theory are preserved in lower dimensions, others are broken, and occasionally, there are symmetry enhancements. The symmetries that are enhanced by toroidal…
The study of cosmic phase transitions are of central interest in modern cosmology. In the standard model of cosmology the Universe begins in a very hot state, right after at the end of inflation via the process of reheating/preheating, and…
The existing cosmological constraints on theories with large extra dimensions rely on the thermal production of the Kaluza-Klein modes of gravitons and radions in the early Universe. Successful inflation and reheating, as well as…
Cosmological phase transitions are predicted by Particle Physics models, and have a variety of important cosmological consequences, which depend strongly on the dynamics of the transition. In this work we investigate in detail the general…
Large extra dimensions, of size of order of TeV^{-1} ~= 10^{-16} cm, arise naturally in the context of supersymmetry breaking in string theory, while strings at a TeV scale offer a solution to the gauge hierarchy problem, as an alternative…
We have studied cosmological constraints on the number and radii of possible large extra dimensions. If such dimensions exist, Kaluza-Klein (KK) modes are copiously produced at high temperatures in the early universe, and can potentially…
Kaluza-Klein compactifications with four-dimensional inflationary geometry combine the attractive idea of higher dimensional models with the attempt to incorporate four-dimensional early-time or late-time cosmology. We analyze the mass…
This article represents the author's PhD thesis which is focused on moduli stabilisation in type IIB Calabi-Yau flux compactifications and its applications to cosmology. I derive the topological conditions on an arbitrary Calabi-Yau to give…
By considering the effects of string winding and momentum modes on a time dependent background, we find a method by which six compact dimensions become stabilized naturally at the self-dual radius while three dimensions grow large.
We construct a model of higher dimensional cosmology in which extra dimensions are frozen by virtue of the cubic-order Lovelock gravity throughout the cosmic history from inflation to the present with radiation and matter-dominated regimes…
We study the effects of extra spacetime dimensions at intermediate mass scales, as expected in string theories with large-radius compactifications, and focus on the gauge and Yukawa couplings within the Minimal Supersymmetric Standard…
We study the thermal confinement/deconfinement and non-thermal quantum phase transitions or rapid cross-overs in QCD and QCD-like theories in external magnetic fields. At large magnetic fields, while the contribution of gauge fluctuations…
We discuss interacting, closed, bosonic and superstrings in thermal equilibrium at temperatures close to the Hagedorn temperature in flat space. We calculate S-matrix elements of the strings at the Hagedorn temperature and use them to…
The partition function of BFSS matrix model is studied for two different classical backgrounds upto 1-loop level. One of the backgrounds correspond to a membrane wrapped around a compact direction and another to a localized cluster of…
In our five-dimensional cosmological model, we investigate the role of a Lorentz violating vector "{\ae}ther" field on the moduli stabilization mechanism. We consider the case of a space-like {\ae}ther field on a compact circle with…
We show that the problem of stabilization of extra dimensions in Kaluza-Klein type cosmology may be solved in a theory of gravity involving high-order curvature invariants. The method suggested (employing a slow-change approximation) can…
Positive vacuum energy together with extra dimensions of space imply that our four-dimensional Universe is unstable, generically to decompactification of the extra dimensions. Either quantum tunneling or thermal fluctuations carry one past…