Parity Measurement in Ultrastrong Coupling Regime

TL;DR

This paper extends a parity measurement scheme for superconducting qubits from the usual rotating-wave approximation to the ultrastrong coupling regime, achieving higher fidelity in quantum measurements.

Contribution

It demonstrates the feasibility and advantages of implementing parity measurement beyond the RWA in ultrastrong coupling, improving measurement fidelity.

Findings

Parity measurement scheme is viable beyond RWA

Ultrastrong coupling enhances measurement fidelity

Potential for improved quantum computing operations

Abstract

The measurement of the parity of two qubits is a primitive of quantum computing that allows creating deterministic entanglement. In the field of circuit quantum electrodynamics, a scheme to achieve parity measurement of two superconducting qubits has been proposed and analyzed under the usual rotating-wave approximation (RWA). We show that the same scheme can be carried over beyond this approximation, to the regime of ultrastrong coupling, with an improvement in the fidelity.