A silicon-based single-electron interferometer coupled to a fermionic sea

TL;DR

This paper demonstrates a silicon-based charge qubit interferometer coupled to a fermionic sea, showing enhanced readout signals and quantum interference effects in a CMOS transistor, advancing solid-state quantum measurement techniques.

Contribution

It introduces a CMOS-compatible single-electron interferometer with projective readout, enabling detailed study of coherent charge dynamics and interference in a solid-state device.

Findings

Multi-passage LZSM interferometry observed

Enhanced dispersive readout signal at large driving amplitudes

Disappearance of interference pattern with multiple projective measurements

Abstract

We study Landau-Zener-Stueckelberg-Majorana (LZSM) interferometry under the influence of projective readout using a charge qubit tunnel-coupled to a fermionic sea. This allows us to characterise the coherent charge qubit dynamics in the strong-driving regime. The device is realised within a silicon complementary metal-oxide-semiconductor (CMOS) transistor. We first read out the charge state of the system in a continuous non-demolition manner by measuring the dispersive response of a high-frequency electrical resonator coupled to the quantum system via the gate. By performing multiple fast passages around the qubit avoided crossing, we observe a multi-passage LZSM interferometry pattern. At larger driving amplitudes, a projective measurement to an even-parity charge state is realised, showing a strong enhancement of the dispersive readout signal. At even larger driving amplitudes, two projective measurements are realised within the coherent evolution resulting in the disappearance of the interference pattern. Our results demonstrate a way to increase the state readout signal of coherent quantum systems and replicate single-electron analogues of optical interferometry within a CMOS transistor.