Nonlinear gravitational-wave memory from cusps and kinks on cosmic strings

Understand

The nonlinear memory effect is a fascinating prediction of general relativity (GR), in which oscillatory gravitational-wave (GW) signals are generically accompanied by a monotonically-increasing strain which persists in the detector long after the signal has passed.

• This effect presents a unique opportunity to test GR in the dynamical and nonlinear regime.
• In this article we calculate the nonlinear memory signal associated with GW bursts from cusps and kinks on cosmic string loops, which are an important target for current and future GW observatories.
• We obtain analytical waveforms for the GW memory from cusps and kinks, and use these to calculate the "memory of the memory" and other higher-order memory effects.