Coupling superconducting flux qubits at optimal point via dynamic decoupling with the quantum bus

TL;DR

This paper introduces a dynamic decoupling scheme with dc-control for superconducting flux qubits at their optimal point, enabling fast, scalable two-qubit gates insensitive to the quantum bus state.

Contribution

It presents a non-perturbative, pulse-based method for coupling flux qubits via a quantum bus, enhancing speed and scalability at the optimal point.

Findings

Effective qubit-qubit coupling achieved

Quantum bus decoupling with pulse sequences

Applicable in non-perturbative coupling regimes

Abstract

We propose a scheme with dc-control of finite bandwidth to implement two-qubit gate for superconducting flux qubits at the optimal point. We provide a detailed non-perturbative analysis on the dynamic evolution of the qubits interacting with a common quantum bus. An effective qubit-qubit coupling is induced while decoupling the quantum bus with proposed pulse sequences. The two-qubit gate is insensitive to the initial state of the quantum bus and applicable to non-perturbative coupling regime which enables rapid two-qubit operation. This scheme can be scaled up to multi-qubit coupling.