Control the qubit-qubit coupling with double superconducting resonators

TL;DR

This paper demonstrates how tuning the frequency difference between qubits and a double-resonator coupler in a superconducting circuit can effectively control qubit-qubit interactions, facilitating scalable quantum computing.

Contribution

It introduces a method to switch and tune qubit-qubit coupling using a double-resonator system, enhancing scalability and reducing noise in superconducting quantum processors.

Findings

Effective coupling can be tuned from off to over 5 MHz by shifting qubit frequencies by about 50 MHz.

Double-resonator coupler simplifies fabrication and reduces flux noise.

Tuning allows dynamic control of qubit interactions for quantum gate operations.

Abstract

We experimentally studied the switching off processes in the double-resonator coupler superconducting quantum circuit. In both frequency and time-domain, we observed the variation of qubit-qubit effective coupling by tuning the frequency differences between qubits and the double-resonator coupler. According to the measurement results, by just shifting about 50 MHz of qubits' frequencies, we can tune the effective qubit-qubit coupling strength from switching off point to two qubit gate point (effective coupling larger than 5 MHz) in double-resonator superconducting quantum circuit.The double-resonator (coupler) superconducting quantum circuit has the advantage of simple fabrications, introducing less flux noises, reducing occupancy of dilution refrigerator cables,which might supply a promising platform for future large-scale superconducting quantum processors.