Electron decoherence in a semiconductor due to electron‐phonon scattering

Abstract

In the present work we study, by means of numerical simulations, the coherent propagation of electrons in quantum wires and focus on the effect of the introduction of roughness along the channel. We study the electron evolution both in single and coupled quantum wires in the case where the electron freely move through the channel and in the case where transport is assisted by surface acoustic waves. It has been shown that systems of coupled quantum wires can realize a complete set of quantum logic gates.However, its physical implementation is severely limited by the spreading of the wave packet and by the presence of interface roughness. Our results show that the potential of the surface acoustic wave succeeds in confining the electron wavefunction and in driving it along the channels also when interface roughness is introduced. This suggests that electron transport assisted by surface acoustic waves could be a very efficient way to realize quantum solid state devices

Wigner transport equation with finite coherence length

“…Among the possible different approaches, the Wigner function (WF) has been widely employed. This function has been succesfully used in several fields of quantum statistical physics, such as molecular, atomic, and nuclear physics, quantum optics, quantum chemistry, quantum entanglement and entropy [1,2,3,4,5,6,7] ‡. In particular, the WF has proved to be very useful for studying quantum electron transport [8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26], owing to its strong analogy with the semiclassical picture, since it explicitly refers to variables defined in an (r,p) Wigner phase space, together with a rigorous description of electron dynamics in quantum terms.…”

Quantum computing with quantum-Hall edge state interferometry

“…Finally, the two beams are recollected on a second BS, where they interfere. In a solid-state implementation of the device, the visibility of AB oscillations in the transmission amplitude measures the degree of coherence for single-electron transport, jeopardized by typical decoherence processes induced by impurities [115,116], phonons [117] or background charges. Thanks to their long-range coherence length, ESs in the IQH proved to be ideal candidates to observe interference patterns in this device.…”

Electron evolution around a repulsive dopant in a quantum wire: coherence effects

“…Since we are interested in highlighting the quantum effects, phonon scattering has been suppressed, both in classical and quantum simulations, even if the simulation framework is able to model this phenomenon 22. In this way we avoid processes of decoherence37 and achieve maximum resolution in comparing classical and quantum simulation results.…”