Fast and Ultrasensitive Electrometer Operating at the Single-Photon Level

Abstract

We demonstrate fast and ultrasensitive charge detection with a cavity-embedded Cooper pair transistor (cCPT) via dispersive readout of its Josephson inductance. We report a minimum charge sensitivity of $14$ $\mu e/\sqrt{\mathrm{Hz}}$ with a detection bandwidth on the order of $1$ MHz using $16$ attowatts of power, corresponding to the single-photon level of the cavity. In addition, our measured sensitivities are within a factor of $5$ of the quantum limit for this device. The single-photon-level sensitivity of the cCPT is comparable to that of the rf-SET, which typically operates using picowatts of power corresponding to hundreds of thousands of photons in its tank circuit. Our results support the feasibility of using the cCPT to mediate an optomechanical interaction that reaches the single-photon strong coupling regime.

References in corpus (8)

• Cooling a nanomechanical resonator with quantum back-action
• Single-photon Optomechanics
• Strong Coupling of a Single Electron in Silicon to a Microwave Photon
• A high-sensitivity gate-based charge sensor in silicon
• Time-domain measurements of quasiparticle tunneling rates in a single-Cooper-pair transistor
• Parity effect in superconducting aluminum single electron transistors with spatial gap profile controlled by film thickness
• Large flux-mediated coupling in hybrid electromechanical system with a transmon qubit
• Highly sensitive and broadband carbon nanotube radio-frequency single-electron transistor

Cited by in corpus (1)

• Charge sensitivity of a cavity-embedded Cooper pair transistor limited by single-photon shot noise