Entangling Superconducting Qubits via Energy-Selective Local Reservoirs

TL;DR

This paper demonstrates a scalable method for stabilizing entangled states in superconducting qubits using engineered, energy-selective reservoirs, advancing quantum state control in open systems.

Contribution

It introduces programmable local reservoirs via parametric coupling, enabling autonomous stabilization of entangled states with high fidelity in superconducting circuits.

Findings

Achieved up to 90.8% fidelity in stabilizing entangled states.

Probed stabilization dynamics under various initial conditions and bath parameters.

Implemented classical shadow estimation for scalable state characterization.

Abstract

Engineered dissipation provides a powerful route to controlling and stabilizing quantum states in open systems. Superconducting circuits are particularly suited to this approach due to their tunable coupling to dissipative environments. Here we realize programmable local reservoirs for superconducting qubits through parametrically driven coupling to readout resonators, creating energy-selective incoherent pump and loss. Using coupled superconducting qubits, we autonomously stabilize entangled single-excitation states with fidelity up to 90.8%. We probe the stabilization dynamics under varying initial conditions and bath parameters, and implement robust classical shadow estimation for accurate and scalable state characterization. Finally, we numerically study a configuration where the engineered pump and loss share a common dissipative mode, leading to reservoir-mediated interference and classically correlated steady states. Our results demonstrate a scalable and hardware-efficient framework for dissipative preparation and control of correlated many-body states in superconducting circuits.