Gravitational wave bursts from cosmic strings

Cusps of cosmic strings emit strong beams of high-frequency gravitational waves (GW). As a consequence of these beams, the stochastic ensemble of gravitational waves generated by a cosmological network of oscillating loops is strongly non-Gaussian, and includes occasional sharp bursts that stand above the rms GW background. These bursts might be detectable by the planned GW detectors LIGO/VIRGO and LISA for string tensions as small as G&mgr; approximately 10(-13). The GW bursts discussed here might be accompanied by gamma ray bursts.     

Gravitational waves from cosmic strings associated with pseudo-Nambu-Goldstone dark matter

We study stochastic gravitational waves from cosmic strings generated in an ultraviolet-complete model for pseudo-Nambu-Goldstone dark matter with a hidden U(1) gauge symmetry.The dark matter candidate in this model can naturally evade direct detection bounds and easily satisfy other phenomenological constraints.The bound on the dark matter lifetime implies an ultraviolet scale higher than 10⁹ GeV.The spontaneous U(1) symmetry breaking at such a high scale would induce cosmic strings ...     

Gravitational waves from cosmic strings after a first-order phase transition

We study the possibility of probing high scale phase transitions that are inaccessible by LIGO. Our study shows that the stochastic gravitational-wave radiation from cosmic strings that are formed after the first-order phase transition can be detected by space-based interferometers when the phase transition temperature is \begin{document}$ T_n\sim {\cal{O}}(10^{8-11}) $\end{document} GeV.     

Cosmic axions from cosmic strings

The possibility of a new constraint on the Peccei-Quinn symmetry breaking scale, arising from the decay of cosmic axion strings, is discussed.     

Gravitational-wave stochastic background from cosmic strings

We consider the stochastic background of gravitational waves produced by a network of cosmic strings and assess their accessibility to current and planned gravitational wave detectors, as well as to big bang nucleosynthesis (BBN), cosmic microwave background (CMB), and pulsar timing constraints. We find that current data from interferometric gravitational wave detectors, such as Laser Interferometer Gravitational Wave Observatory (LIGO), are sensitive to areas of parameter space of cosmic string models complementary to those accessible to pulsar, BBN, and CMB bounds. Future more sensitive LIGO runs and interferometers such as Advanced LIGO and Laser Interferometer Space Antenna (LISA) will be able to explore substantial parts of the parameter space.