TY - JOUR

T1 - Rotational perturbations in Neveu-Schwarz-Neveu-Schwarz string cosmology

AU - Chen, Chiang Mei

AU - Harko, T.

AU - Mak, M. K.

PY - 2001

Y1 - 2001

N2 - First order rotational perturbations of the flat Friedmann-Robertson-Walker metric are considered in the framework of four dimensional Neveu-Schwarz-Neveu-Schwarz string cosmological models coupled with dilaton and axion fields. For the H field we use the solitonic ansatz, assuming that it is a function of time only. The decay rate of rotation depends mainly upon the dilaton field potential U. The equation for rotation imposes strong limitations upon the functional form of U, restricting the allowed potentials to two: the trivial case U = 0 and a generalized exponential type potential. In these two models the metric rotation function can be obtained in an exact analytic form in both Einstein and string frames. In the potential-free case the decay of rotational perturbations is governed by an arbitrary function of time while in the presence of a potential the rotation tends rapidly to zero in both Einstein and string frames.

AB - First order rotational perturbations of the flat Friedmann-Robertson-Walker metric are considered in the framework of four dimensional Neveu-Schwarz-Neveu-Schwarz string cosmological models coupled with dilaton and axion fields. For the H field we use the solitonic ansatz, assuming that it is a function of time only. The decay rate of rotation depends mainly upon the dilaton field potential U. The equation for rotation imposes strong limitations upon the functional form of U, restricting the allowed potentials to two: the trivial case U = 0 and a generalized exponential type potential. In these two models the metric rotation function can be obtained in an exact analytic form in both Einstein and string frames. In the potential-free case the decay of rotational perturbations is governed by an arbitrary function of time while in the presence of a potential the rotation tends rapidly to zero in both Einstein and string frames.

UR - http://www.scopus.com/inward/record.url?scp=85038308650&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.63.104013

DO - 10.1103/PhysRevD.63.104013

M3 - 期刊論文

AN - SCOPUS:0034899554

VL - 63

JO - Physical Review D - Particles, Fields, Gravitation and Cosmology

JF - Physical Review D - Particles, Fields, Gravitation and Cosmology

SN - 0556-2821

IS - 10

M1 - 104013

ER -