Parametric coupling for superconducting qubits

TL;DR

This paper introduces a parametric coupling scheme for superconducting qubits that enables rapid, tunable two-qubit gates by modulating the coupling at specific frequencies, promising faster quantum operations.

Contribution

The paper presents a novel parametric coupling method for superconducting qubits that allows fast, switchable interactions at their symmetry points, enhancing quantum gate speed and control.

Findings

Coupling can be modulated at nanosecond timescales.

Resonance achieved via frequency sum or difference modulation.

Potential for rapid two-qubit gate implementation.

Abstract

We propose a scheme to couple two superconducting charge or flux qubits biased at their symmetry points with unequal energy splittings. Modulating the coupling constant between two qubits at the sum or difference of their two frequencies allows to bring them into resonance in the rotating frame. Switching on and off the modulation amounts to switching on and off the coupling which can be realized at nanosecond speed. We discuss various physical implementations of this idea, and find that our scheme can lead to rapid operation of a two-qubit gate.