Quantum entanglement and drifting generated by an ac field resonant with frequency-doubled Bloch oscillations of correlated particles

Abstract

We study the dynamics of initially localized and uncorrelated two-particle quantum wave packets evolving in a one-dimensional discrete lattice. In particular, we show that the particles become strongly entangled when directed by a harmonic ac field which is resonant with frequency-doubled Bloch oscillations promoted by a static dc field. Some degree of entanglement is also achieved when the ac field is resonant with the single-particle Bloch oscillations. However, in this case, entanglement is strongly limited by the survival of anticorrelated unbounded states. We further show that the drift velocity of the correlated-particle wave-packet centroid depends on the phase of the ac field. This dependence is similar to the semiclassical prediction for single-particle motion. The drift velocity vanishes in the limit of uncorrelated particles, as well as for Fock-like initial states, which have a null expectation value of the kinetic operator. We reveal that the interparticle interaction influences unbounded- and bounded-state components differently. This leads to a nontrivial nonmonotonic dependence of the drift velocity on the interaction strength.