Ultra-dispersive resonator readout of a quantum-dot qubit using longitudinal coupling

TL;DR

This paper demonstrates a novel method for reading out a quantum-dot qubit using longitudinal coupling to a superconducting resonator, enabling ultra-dispersive regime operation in circuit QED.

Contribution

It introduces a parametric longitudinal coupling mechanism for quantum-dot qubits, expanding the capabilities of semiconductor qubit readout in the ultra-dispersive regime.

Findings

Successful readout of a quantum-dot hybrid qubit via longitudinal coupling

Operation in the ultra-dispersive regime with 10 GHz detuning

Potential for improved qubit measurement fidelity

Abstract

We perform readout of a quantum-dot hybrid qubit coupled to a superconducting resonator through a parametric, longitudinal interaction mechanism. Our experiments are performed with the qubit and resonator frequencies detuned by $\sim$10 GHz, demonstrating that longitudinal coupling can facilitate semiconductor qubit operation in the 'ultra-dispersive' regime of circuit quantum electrodynamics.