Generation of squeezed states in coupled cavity chains via dissipation of gap-tunable qubits

A dissipative scheme is proposed to generate single- or two-mode squeezed states in a hybrid quantum system consisting of superconducting resonators and nitrogen-vacancy-center ensembles (NVEs). For the single-mode squeezing generation, we consider an array of linearly coupled superconducting resonators, each of which is magnetically coupled to a NVE. In addition, one of the resonators is coupled to a gap-tunable qubit. It is shown that at steady state all the resonators and NVEs in the array can enter into single-mode squeezed states via dissipation of the qubit. For the two-mode squeezing realization, we consider a pair of superconducting resonator chains, which are coupled to two gap-tunable qubits. We find that at steady state all the resonator pairs in the up and down chains will be steered into two-mode squeezed states via dissipation of the qubits. The present scheme has a remarkable feature: only one or two gap-tunable dissipative qubits are locally involved, and no squeezing resource is required.