Coupling-modulation–mediated generation of stable entanglement of superconducting qubits via dissipation

Abstract

We propose an experimentally feasible scheme for the dissipative generation of stable entanglement of superconducting qubits via coupling modulation without applying any drives on qubits and resonator. Firstly, we study the circuit of one superconducting transmission line resonator coupled to two separated qubits via two superconducting quantum interference devices (SUQIDs). By modulating the inductance of the SQUIDs via external fluxes, we can tailor an appropriate qubit-resonator couplings with both red- and blue-sideband interactions. Combined with the photon loss of the resonator, the two qubits can be autonomously steered into a long-lived entangled state with high-fidelity. Moreover, we extend the model to one resonator coupled to two separated qubit chains, each of which contains $N$ linearly coupled superconducting qubits. We show that the lossy resonator can drive the whole system into a unique dark state, i.e., a series of $N$ entangled pairs of qubits across the chains can be stabilized at the stationary state. So, the present work enables the preparation of stable long-range entangled state between the two qubits in the end sites of the chains, which plays important role for implementing scalable quantum computation and quantum communication.