相关论文: Antisymmetric field in string gas cosmology

Scale factor duality, a truncated form of time dependent T-duality, is a symmetry of string effective action in cosmological backgrounds interchanging small and large scale factors. The symmetry suggests a cosmological scenario…

We propose a mechanism for solving the horizon and entropy problems of standard cosmology which does not make use of cosmological inflation. Crucial ingredients of our scenario are brane gases, extra dimensions, and a confining potential…

We use the recently modified Friedmann equations obtained from string T-duality effects that encode the zero-point length (Phys. Lett. B 836 (2023), 137621) to study the phase space analyses of a bouncing early universe. An important…

String gas cosmology is an approach towards studying the effects of superstring theory on early universe cosmology which is based on new symmetries and new degrees of freedom of string theory. Within this context, it appears possible to…

Vacuum polarization effects in the cosmic string background are considered. We find that a current is induced in the vacuum of the quantized massive scalar field and that the current circulates around the string which is generalized to a…

In this paper we study the effect of the magnetic field in string cosmology for a spatially homogenous and anisotropic Bianchi type -V space-time model. In order to study the effect of magnetic field, the standard form of the energy…

We introduce a very early universe model based on the thermodynamics of a gas of closed strings in a background which is non-perturbative in $\alpha'$. Upon considering the fully $\alpha'$-corrected equations extended to include certain…

We consider the spacetime dynamics of a gas of closed strings in the context of General Relativity in a background of arbitrary spatial dimensions. Our motivation is primarily late time String Gas Cosmology, where such a spacetime picture…

Aspects of string cosmology for critical and non-critical strings are discussed emphasizing the necessity to account for the dilaton dynamics for a proper incorporation of ``large - small" duality. This drastically modifies the intuition…

We consider the anisotropic evolution of spatial dimensions and the stabilization of internal dimensions in the framework of brane gas cosmology. We observe that the bulk RR field can give an effective potential which prevents the internal…

In recent works we developed a model of balanced gas flow where the momentum equation possesses an additional mean field forcing term, which originates from the hard sphere interaction potential between the gas particles. We demonstrated…

A novel mechanism to produce a cosmic network of fundamental superstrings based on a time-varying string tension has been recently proposed. It has been found that fundamental superstrings can grow in a kinating background driven by the…

In this paper we derive some new invariant solutions of Einstein-Maxwell's field equations for string fluid as source of matter in cylindrically symmetric space-time with Variable Magnetic Permeability. We also discuss the physical and…

We study the cosmological evolution based upon a $D$-dimensional action in low-energy effective string theory in the presence of second-order curvature corrections and a modulus scalar field (dilaton or compactification modulus). A…

We study the cosmological evolution of a type-0 string theory by employing non-criticality, which may be induced by fluctuations of the D3 brane worlds. We check the consistency of the approach to O(alpha ') in the corresponding…

Exact cosmological solutions are obtained for a five dimensional inhomogeneous fluid distribution along with a Brans-Dicke type of scalar field. The set includes varied forms of matter field including $\rho+p=0$, where p is the 3D isotropic…

We investigate a class of cosmological solutions of Einstein's field equations in higher dimensions with a cosmological constant and an ideal fluid matter distribution as a source. We discuss the dynamical evolution of the universe subject…

Starting from an exact (in the Regge slope alpha') functional method for a bosonic stringy sigma-model, we investigate four-dimensional cosmological string solutions in graviton, dilaton and antisymmetric tensor backgrounds, compatible with…

We explore the possibility of parity-violating, nonminimally coupled 2-form field theories that retain the same dynamical degrees of freedom as a massive 2-form and thus are ghost-free. Starting from the most general kinetic terms and…

Based on the assumption that the target space duality ($T\to 1/T$) is preserved even nonperturbatively, the properties of static string vacua are studied. A discussion of the effective four-dimensional supergravity action based on…