Resonant Schr\"odinger Cat States in Circuit Quantum Electrodynamics

TL;DR

This paper introduces a rapid method to generate Schr"odinger cat states in superconducting resonators via a continuously driven qubit, avoiding complex regimes and dissipation engineering, with analysis and simulations confirming its effectiveness.

Contribution

It presents a novel, fast scheme for creating Schr"odinger cat states in circuit QED without relying on dispersive regimes or engineered dissipation, including analysis for different qubit resonance conditions.

Findings

The scheme efficiently generates cat states in realistic conditions.

Analytical results match numerical simulations with decoherence effects.

Applicable to weakly and strongly-anharmonic qutrits.

Abstract

We propose a fast scheme to generate Schr\"odinger cat states in a superconducting resonator using a continuously driven qubit without resorting to the dispersive regime, two-photon drives, or engineered two-photon dissipation. We provide analysis for when the qubit is on and off resonance from the drive. We extend our analysis to account for a third level in a weakly-anharmonic qutrit. We also discuss the case of a strongly-anharmonic qutrit. Throughout the paper, we corroborate our analytical results with numerical simulations in the presence of energy relaxation and dephasing of the qubit and resonator using realistic experimental parameters.