Coherent Particle Transfer in an On-Demand Single-Electron Source

TL;DR

This paper models coherent single-electron transfer in quantum dots, revealing conditions for noiseless transfer without particle-hole excitations and proposing a detection scheme for coherence analysis.

Contribution

It introduces a Floquet scattering matrix approach to describe inelastic transitions and identifies protocols for noiseless electron transfer in on-demand sources.

Findings

Noiseless transfer occurs with linear energy ramping

Particle-hole excitations can be avoided under specific driving protocols

A detection scheme for coherence is proposed

Abstract

Coherent electron transfer from a localized state trapped in a quantum dot into a ballistic conductor, taking place in on-demand electron sources, in general may result in excitation of particle-hole pairs. We consider a simple model for these effects, involving a resonance level with time-dependent energy, and derive Floquet scattering matrix describing inelastic transitions of particles in the Fermi sea. We find that, as the resonance level is driven through the Fermi level, particle transfer may take place completely without particle-hole excitations for certain driving protocols. In particular, such noiseless transfer occurs when the level moves with constant rapidity, its energy changing linearly with time. A detection scheme for studying the coherence of particle transfer is proposed.