Non-local detection of resistance fluctuations of an open quantum dot

TL;DR

This paper studies quantum fluctuations in the non-local resistance of an open quantum dot, combining experimental measurements with theoretical analysis to understand the effects of coupling and dephasing.

Contribution

It provides the first detailed experimental characterization of non-local resistance fluctuations in an open quantum dot and compares results with Landauer-Büttiker theory, highlighting the role of dephasing.

Findings

Resistance fluctuations of several hundreds of Ohms observed

Fluctuation amplitude decreases with increased coupling to voltage probes

Theoretical predictions match experimental data when dephasing is included

Abstract

We investigate quantum fluctuations in the non-local resistance of an open quantum dot which is connected to four reservoirs via quantum point contacts. In this four-terminal quantum dot the voltage path can be separated from the current path. We measured non-local resistance fluctuations of several hundreds of Ohms, which have been characterized as a function of bias voltage, gate voltage and perpendicular magnetic field. The amplitude of the resistance fluctuations is strongly reduced when the coupling between the voltage probes and the dot is enhanced. Along with experimental results, we present a theoretical analysis based on the Landauer-B\"{u}ttiker formalism. While the theory predicts non-local resistance fluctuations of considerably larger amplitude than what has been observed, agreement with theory is very good if an additional dephasing mechanism is assumed.