Mesoscopic threshold detectors: Telegraphing the size of a fluctuation

TL;DR

This paper introduces a novel on-chip mesoscopic detector that uses current instability to measure shot noise and fluctuation statistics, enabling indirect access to current fluctuations through telegraph processes.

Contribution

It presents a new method for measuring shot noise in mesoscopic systems by exploiting an instability in the I-V characteristic, using a quantum double dot as a threshold detector.

Findings

The method allows extraction of shot noise power from I-V curves.

Switching rates reveal the extreme value statistics of current fluctuations.

The approach provides an indirect way to access full current statistics.

Abstract

We propose a two-terminal method to measure shot noise in mesoscopic systems based on an instability in the current-voltage characteristic of an on-chip detector. The microscopic noise drives the instability, which leads to random switching of the current between two values, the telegraph process. In the Gaussian regime, the shot noise power driving the instability may be extracted from the I-V curve, with the noise power as a fitting parameter. In the threshold regime, the extreme value statistics of the mesoscopic conductor can be extracted from the switching rates, which reorganize the complete information about the current statistics in an indirect way, "telegraphing" the size of a fluctuation. We propose the use of a quantum double dot as a mesoscopic threshold detector.