W.S. Dias

Unidirectional quantum walk of two correlated particles: Manipulating bound-pair and unbound wave-packet components

Abstract We study the unidirectional transport of two-particle quantum wave-packets in a regular one-dimensional lattice. We show that the bound-pair state component behaves differently from unbound states when subjected to an external pulsed electric field. Thus, strongly entangled particles exhibit a quite distinct dynamics when compared to a single particle system. With respect to centroid motion, our numerical results are corroborated with an analytical expression obtained using a semi-classical approach. The wave function profile reveals that the particle–particle interaction induces the splitting of the initial wave-packet into two branches that propagate with specific directions and drift velocities. With a proper external field tuning, the wave-packet components can perform an unidirectional transport on the same or opposite directions. The amplitude of each mode is related to the degree of entanglement between particles, which presents a non monotonic dependence on the interaction strength.

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

We show that initially localized and uncorrelated two-particles quantum wavepackets evolving in a one-dimensional discrete lattice become strongly entangled while drifting under the action of an harmonic AC field resonant with doubled Bloch oscillations promoted by a static DC field. Although partial entanglement is achieved when the AC field is resonant with the single-particle Bloch oscillations, it is strongly limited by the survival of anti-correlated unbounded states. We further show that the phase dependence of the wavepacket centroid velocity is similar to the semiclassical behavior depicted by a single-particle. However, the drift velocity exhibits a non-trivial non-monotonic dependence on the interaction strength, vanishing in the limit of uncorrelated particles, that unveils its competing influence on unbounded and bounded states.