Steady state entanglement of two superconducting qubits engineered by dissipation

TL;DR

This paper proposes a robust method to generate and maintain a maximally entangled state of two superconducting qubits in a circuit QED setup using engineered dissipation and microwave drives, verified through analytical and numerical analysis.

Contribution

It introduces a dissipative scheme combining photon loss and microwave driving to prepare and sustain entanglement in superconducting qubits, adaptable to current experimental setups.

Findings

High fidelity entangled steady states achievable

Scheme robust to experimental imperfections

Applicable to both 3D and 2D transmon qubits

Abstract

We present a scheme for the dissipative preparation of an entangled steady state of two superconducting qubits in a circuit QED setup. Combining resonator photon loss, a dissipative process already present in the setup, with an effective two-photon microwave drive, we engineer an effective decay mechanism which prepares a maximally entangled state of the two qubits. This state is then maintained as the steady state of the driven, dissipative evolution. The performance of the dissipative state preparation protocol is studied analytically and verified numerically. In view of the experimental implementation of the presented scheme we investigate the effects of potential experimental imperfections and show that our scheme is robust to small deviations in the parameters. We find that high fidelities with the target state can be achieved both with state-of-the-art 3D, as well as with the more commonly used 2D transmons. The promising results of our study thus open a route for the demonstration of an entangled steady state in circuit QED.