Speaker
Description
Cosmic strings can be produced during phase transitions in the very
early universe. They are particularly interesting objects since they
emit gravitational waves contributing to the stochastic gravitational
wave background (SGWB). This gives us possibility to connect
gravitational waves experiments to unknown physics scenarios of the very
distant past. In the early stages of cosmic string network evolution we
expect frequent interactions of cosmic strings with particles of the
surrounding plasma. Usually in the literature the contribution to the
SGWB from these friction-dominated regimes is neglected. In our work,
however, we show that, for a significant part of parameter space, the
inclusion of friction leads to a prominent signature in the ultra-high
frequency range of the spectrum. More than that, this signature should
be sensitive to the particular underlying high energy physics scenarios,
depending not only on the fields that constitute the string but also on
the particle contents of the early universe. In order to ease an
investigation of the signature's dependence on free parameters we
developed analytical approximations to the SGWB created by cosmic
strings during the friction era for the most relevant cases.
