Tuning coupling between superconducting resonators with collective qubits

TL;DR

This paper presents a quantum switch that dynamically tunes the coupling between superconducting resonators using collective qubit states, enabling rapid control for quantum information applications.

Contribution

It introduces a method to control resonator coupling via engineered collective qubit states, achieving fast switching without altering qubit frequencies.

Findings

Coupling strength can be tuned from zero to a large value proportional to qubit number.

Switching occurs within nanoseconds without changing qubit transition frequencies.

Potential applications include quantum simulation and information processing.

Abstract

By simultaneously coupling multiple two-level artificial atoms to two superconducting resonators, we design a quantum switch that tunes the resonator-resonator coupling strength from zero to a large value proportional to the number of qubits. This process is implemented by engineering the qubits into different subradiant states, where the microwave photons decay from different qubits destructively interfere with each other such that the resonator-resonator coupling strength keeps stable in an open environment. Based on a three-step control scheme, we switch the coupling strength among different values within nanoseconds without changing the transition frequency of the qubits. We also apply the quantum switch to a network of superconducting resonators, and demonstrate its potential applications in quantum simulation and quantum information storage and processing.