Single electron transport and entanglement induced by surface acoustic waves versus free ballistic propagation in coupled quantum wires

Surface acoustic waves (SAW) have proved to be a valuable mean to control single-electron dynamics in nano-devices. In this paper, we study the coherent propagation of electrons in quantum wires driven by SAW, as a part of a feasibility study on a coupled quantum wires device, able to realize the basic operations needed for quantum computing. Such a system has already been proposed and studied by the group of the authors in the case of free electron propagation. The new idea now pursued is that the results obtained should be significantly improved by using SAW. Three main advantages can be identified: 1) two or more electrons can be injected simultaneously in different wires, 2) since the electron wavefunction is embedded in a "moving quantum dot" formed by the minimum of the SAW and the wire barriers, its natural spread is not present during the propagation, 3) the electron in the SAW minimum could be more immune to the decohering effects of phonons. In order to study the evolution of the electron wavefunction in presence of the time-dependent SAW potential, we perform two types of time-dependent simulations: the 1) single-particle/two-dimensions and the 2) two one-dimensional particles.