Adiabatic fluctuations from cosmic strings in a contracting universe

作者：Brandenberger Robert H^*; Takahashi Tomo; Yamaguchi Masahide

来源：Journal of Cosmology and Astroparticle Physics, 2009, 2009(7): 015.

DOI：10.1088/1475-7516/2009/07/015

• Cosmic strings
• domain walls
• monopoles
• cosmological perturbation theory
• string theory and cosmology
• physics of the early universe

We show that adiabatic, super-Hubble, and almost scale invariant density fluctuations are produced by cosmic strings in a contracting universe. An essential point is that isocurvature perturbations produced by topological defects such as cosmic strings on super-Hubble scales lead to a source term which seeds the growth of curvature fluctuations on these scales. Once the symmetry has been restored at high temperatures, the isocurvature seeds disappear, and the fluctuations evolve as adiabatic ones in the expanding phase. Thus, cosmic strings may be resurrected as a mechanism for generating the primordial density fluctuations observed today.

• 出版日期2009-7