Probing the Quantum Capacitance of Rydberg Transitions of Surface Electrons on Liquid Helium via Microwave Frequency Modulation

Abstract

We present a method for probing the quantum capacitance associated with the Rydberg transition of surface electrons on liquid helium using radio-frequency (RF) reflectometry. Resonant microwave excitation of the Rydberg transition induces a redistribution of image charges on capacitively coupled electrodes, giving rise to a quantum capacitance originating from adiabatic state transitions and the finite curvature of the energy bands. By applying frequency-modulated resonant microwaves to drive the Rydberg transition, we systematically measured a capacitance sensitivity of 0.34~aF/$\sqrt{\mathrm{Hz}}$ for our RF reflectometry scheme. This sensitivity is sufficient to detect the Rydberg transition of a single electron, offering a scalable pathway toward qubit readout schemes based on surface electrons on helium.

References in corpus (3)

• Efficient and robust analysis of complex scattering data under noise in microwave resonators
• A high-sensitivity gate-based charge sensor in silicon
• Spin-orbit couplings between distant electrons trapped individually on liquid helium

Cited by in corpus (1)

• Internal cyclotron probe of the vertical polarizability of a surface-state electron on helium