A tunable coupling scheme for implementing high-fidelity two-qubit gates

TL;DR

This paper introduces a tunable coupling scheme for superconducting qubits that enables high-fidelity two-qubit gates by controlling the coupler frequency, reducing parasitic errors, and improving scalability.

Contribution

The authors propose a generalizable, dispersive regime-based coupler switch scheme that enhances two-qubit gate fidelity in superconducting circuits.

Findings

Errors from parasitic effects are strongly suppressed.

The scheme is compatible with existing high-coherence hardware.

Simulations show improved gate performance.

Abstract

The prospect of computational hardware with quantum advantage relies critically on the quality of quantum gate operations. Imperfect two-qubit gates is a major bottleneck for achieving scalable quantum information processors. Here, we propose a generalizable and extensible scheme for a two-qubit coupler switch that controls the qubit-qubit coupling by modulating the coupler frequency. Two-qubit gate operations can be implemented by operating the coupler in the dispersive regime, which is non-invasive to the qubit states. We investigate the performance of the scheme by simulating a universal two-qubit gate on a superconducting quantum circuit, and find that errors from known parasitic effects are strongly suppressed. The scheme is compatible with existing high-coherence hardware, thereby promising a higher gate fidelity with current technologies.