Detection of finite frequency photo-assisted shot noise with a resonant circuit

TL;DR

This paper proposes a method to detect finite frequency photo-assisted shot noise in mesoscopic conductors using a resonant circuit, even without time translational invariance, and demonstrates its effectiveness in fractional quantum Hall systems.

Contribution

It extends existing detection schemes to photo-assisted shot noise, showing how to measure it via a resonant circuit despite the absence of time translational invariance.

Findings

Photo-assisted shot noise shows peaks at the DC bias frequency.

Satellite peaks appear separated by the AC drive frequency.

The method is tested on fractional quantum Hall point contacts.

Abstract

Photo-assisted transport through a mesoscopic conductor occurs when an oscillatory (AC) voltage is superposed to the constant (DC) bias which is imposed on this conductor. Of particular interest is the photo assisted shot noise, which has been investigated theoretically and experimentally for several types of samples. For DC biased conductors, a detection scheme for finite frequency noise using a dissipative resonant circuit, which is inductively coupled to the mesoscopic device, was developped recently. We argue that the detection of the finite frequency photo-assisted shot noise can be achieved with the same setup, despite the fact that time translational invariance is absent here. We show that a measure of the photo-assisted shot noise can be obtained through the charge correlator associated with the resonant circuit, where the latter is averaged over the AC drive frequency. We test our predictions for a point contact placed in the fractional quantum Hall effect regime, for the case of weak backscattering. The Keldysh elements of the photo-assisted noise correlator are computed. For simple Laughlin fractions, the measured photo-assisted shot noise displays peaks at the frequency corresponding to the DC bias voltage, as well as satellite peaks separated by the AC drive frequency.