Sensing and Control of Single Trapped Electrons Above 1 Kelvin

TL;DR

This paper demonstrates the detection and control of single electrons trapped above liquid helium at temperatures above 1 Kelvin using a superconducting resonator, advancing quantum information processing capabilities.

Contribution

It introduces a method for spatial control and detection of single electrons at higher temperatures than previously achieved, using dispersive readout with a superconducting resonator.

Findings

Successful detection of single electrons via frequency shifts

Agreement between experimental data and classical oscillator model

Potential for scalable quantum processors at >1 K

Abstract

Electrons trapped on the surface of cryogenic substrates (liquid helium, solid neon or hydrogen) are an emerging platform for quantum information processing made attractive by the inherent purity of the electron environment, the scalability of trapping devices and the predicted long lifetime of electron spin states. Here we demonstrate the spatial control and detection of single electrons above the surface of liquid helium at temperatures above 1 K. A superconducting coplanar waveguide resonator is used to read out the charge state of an electron trap defined by gate electrodes beneath the helium surface. Dispersive frequency shifts are observed as the trap is loaded with electrons, from several tens down to single electrons. These frequency shifts are in good agreement with our theoretical model that treats each electron as a classical oscillator coupled to the cavity field. This sensitive charge readout scheme can aid efforts to develop large-scale quantum processors that require the high cooling powers available in cryostats operating above 1 K.