Displacement memory and B-memory in generalised Ellis-Bronnikov wormholes

Abstract: Gravitational wave (GW) memory effect is studied in the context of generalised Ellis-Bronnikov (GEB) wormholes. We solved the geodesic equations in this wormhole spacetime, in the presence of a GW pulse. The resulting evolution of the geodesic separation shows the presence of displacement and velocity memory. Memory effect due to a gravitational wave ensures that there is a permanent effect on spacetime geometry. The corresponding geodesic evolution, being metric dependent, would display distinct results in each case. Motivated by the same, we study further aspects of memory effect on the geodesic congruences, known as the B-memory, by solving the Raychaudhuri equations. Since future GW detectors will be able to probe the memory effect, our work presents GEB spacetime as a black hole mimicker with distinguishing features.