Near-Unity Charge Readout in a Nonlinear Resonator without Matching

TL;DR

This paper demonstrates that nonlinear resonators can achieve near-unity charge readout signals without impedance matching, significantly increasing bandwidth and enabling ultra-fast quantum dot charge detection.

Contribution

We show that operating a nonlinear resonator in the nonlinear regime allows high-fidelity charge readout without impedance matching, expanding the potential for rapid quantum measurements.

Findings

Achieved near-unity signal in nonlinear regime without matching

Bandwidth increased by an order of magnitude

Signal enhancement due to sensor dissipation effects

Abstract

In this paper, we present a nonlinear resonator performing the readout of a charge-sensing quantum dot. We show that by driving the resonator in the nonlinear regime, we achieve a near-unity signal. This despite not satisfying the impedance matching requirements necessary for such large signals in the linear regime. Our experiments, supported by numerical calculations, demonstrate that the signal increase stems from the sensor dissipation shifting the onset of the nonlinear resonator response. By lifting the matching requirement, we increase the bandwidth limit of resonator readout-based charge detection by an order of magnitude, opening up the avenue to ultra-fast charge detectors.