Strong suppression of shot noise in a feedback-controlled single-electron transistor

TL;DR

This paper demonstrates how electronic feedback control can significantly suppress shot noise in a single-electron transistor, advancing quantum transport measurement precision and mimicking quantum optics techniques.

Contribution

It introduces a novel electronic feedback method to suppress shot noise in a single-electron transistor, achieving noise freezing and enhanced control over charge fluctuations.

Findings

Stronger shot noise suppression with increased feedback response

Faster freezing of charge current fluctuations

Analogous to squeezed light generation in quantum optics

Abstract

Feedback control of quantum mechanical systems is rapidly attracting attention not only due to fundamental questions about quantum measurements but also because of its novel applications in many fields in physics. Quantum control has been studied intensively in quantum optics but recently progress has been made in the control of solid-state qubits as well. In quantum transport only a few active and passive feedback experiments have been realized on the level of single-electrons, though theoretical proposals exist. Here we demonstrate the suppression of shot noise in a single-electron transistor, using an exclusively electronic closed-loop feedback to monitor and adjust the counting statistics. With increasing feedback response we observe a stronger suppression and faster freezing of charge current fluctuations. Our technique is analog to the generation of squeezed light with in-loop photodetection as used in quantum optics. Sub-Poisson single-electron sources will pave the way for high precision measurements in quantum transport similar to its optical or opto-mechanical equivalent.