Persistent oscillations after quantum quenches in d dimensions

Space of initial conditions and universality in nonequilibrium quantum dynamics

“…The fact that the low energy modes dominate the large time dynamics in the general case of interacting quasiparticles is known for quantum quenches [5,6,7,8]. 8 Fine tuning of the functions fn can lead to peculiar states. These, however, will form some zero measure subset, and typically will not be physically relevant.…”

“…If for t < 0 the system was in the ground state of the pre-quench Hamiltonian H 0 , the nonequilibrium post-quench state |ψ is dynamically generated, with the coefficients of the superposition entirely determined by the quench. The analytical determination of |ψ is nontrivial, but the general formalism has been developed in the last years [5,6,7,8]. It shows, in particular, how |ψ depends on the equilibrium universality class and how the transformation properties of the quench operator under the group G affect the dynamics at large times.…”

Variations on vacuum decay: the scaling Ising and tricritical Ising field theories

“…The origin of these oscillations is that the quench excites the metastable particle states over the false vacuum discussed above. The presence of such oscillations in expectation values of local operators can be regarded as a generic feature of quantum quenches when there is a one-particle contribution to the time evolution and it can be established by using first order perturbation theory [36][37][38]; such oscillations were also observed in the time evolution of entanglement [39]. We note that, contrary to the results obtained in first order perturbation theory, these oscillations are in general exponentially damped, as shown by explicit simulations of the time evolution [27]; however, the exponential damping can only be obtained by summing up the contribution of kinematic poles to all orders [40,41] and is therefore inaccessible in leading order perturbation theory.…”