Gravitational waves from melting cosmic strings. Issue 1 (1st January 2022)

• Record Type: Journal Article
• Authors: Emond, William T.; Ramazanov, Sabir; Samanta, Rome
• Is Part Of: Journal of cosmology and astroparticle physics. Volume 2022:Issue 1(2022)
• Publication Date: 2022-01-01
• Subjects: Cosmic strings -- domain walls -- monopoles -- gravitational waves / sources -- cosmology of theories beyond the SM; Cosmology -- Periodicals; Astrophysics -- Periodicals; 523.0105
• DOI: 10.1088/1475-7516/2022/01/057
• Languages: English
• ISSNs: 1475-7516

Abstract

Abstract: Appearance of cosmic strings in the early Universe is a common manifestation of new physics typically linked to some high energy scale. In this paper, we discuss a different situation, where a model underlying cosmic string formation is approximately scale free. String tension is naturally related to the square of the temperature of the hot primordial plasma in such a setting, and hence decreases with (cosmic) time. With gravitational backreaction neglected, the dynamics of these melting strings in an expanding Universe is equivalent to the dynamics of constant tension strings in a Minkowski spacetime. We provide an estimate for the emission of gravitational waves from string loops. Contrary to the standard case, the resulting spectrum is markedly non-flat and has a characteristic falloff at frequencies below the peak one. The peak frequency is defined by the underlying model and lies in the range accessible by the future detectors for very weak couplings involved.