Spectrum of relic gravitational waves in string cosmology

TL;DR

This paper calculates the spectrum of relic gravitational waves in string cosmology, revealing oscillations that could produce detectable signals at current gravitational wave observatories like LIGO and VIRGO.

Contribution

It provides a comprehensive spectrum including oscillations, extending known results and identifying potential observable signatures in gravitational wave detectors.

Findings

Spectrum shows characteristic oscillations.

Signal can reach detectable levels at LIGO/VIRGO frequencies.

Potential for early detection with current experiments.

Abstract

We compute the spectrum of relic gravitons in a model of string cosmology. In the low- and in the high-frequency limits we reproduce known results. The full spectrum, however, also displays a series of oscillations which could give a characteristic signature at the planned LIGO/VIRGO detectors. For special values of the parameters of the model the signal reaches its maximum already at frequencies accessible to LIGO and VIRGO and it is close to the sensitivity of first generation experiments.