Plane Gravitational Waves, the Kinetic Energy of Free Particles and the Memory Effect

Resumo

It is shown that in the passage of a short burst of nonlinear plane gravitational wave, the kinetic energy of free particles may either decrease or increase. The decrease or increase of the kinetic energy crucially depends on the initial conditions (position and velocity) of the a particle. Therefore a plane gravitational wave may extract energy from a physical system.