Speaker
Description
Cosmic strings are one-dimensional topological defects, which are formed during symmetry-breaking phase transitions with a non-simply connected vacuum manifold. If they exist, they are expected to generate gravitational waves, which we might be able to detect with future gravitational wave observatories such as LISA or Einstein Telescope. In particular, local features on the strings, such as kinks and cusps, would produce distinctive gravitational waveforms.
The evolution of these strings can be approximately modelled using Nambu-Goto dynamics, which can then be used to calculate the gravitational wave signals they emit. In previous such calculations the effect of the gravitational backreaction of the string onto itself was neglected. However, since the gravitational self-force is particularly important for kinks and cusps we would expect it to especially affect the gravitational waves produced by these features.
By modelling how simple cosmic string loops evolve under the effect of their own gravity we find that the gravitational backreaction suppresses the formation of cusps. This subsequently leads to a high-frequency cut-off in the gravitational wave signal they produce, which has important implications for detecting such signals with future observatories.