Dephasing in sequential tunneling through a double-dot interferometer

TL;DR

This paper investigates how environmental interactions cause dephasing in electron tunneling through a double-dot interferometer, affecting quantum interference and current flow.

Contribution

It introduces a model treating tunneling perturbatively while accounting for bath coupling to analyze dephasing effects in quantum dot interference.

Findings

Bath spectra influence interference visibility

Dephasing can be distinguished from renormalization effects

Finite tunneling current reappears due to dephasing

Abstract

We analyze dephasing in a model system where electrons tunnel sequentially through a symmetric interference setup consisting of two single-level quantum dots. Depending on the phase difference between the two tunneling paths, this may result in perfect destructive interference. However, if the dots are coupled to a bath, it may act as a which-way detector, leading to partial suppression of the phase-coherence and the reappearance of a finite tunneling current. In our approach, the tunneling is treated in leading order whereas coupling to the bath is kept to all orders (using P(E) theory). We discuss the influence of different bath spectra on the visibility of the interference pattern, including the distinction between "mere renormalization effects" and "true dephasing".