A simple all-microwave entangling gate for fixed-frequency superconducting qubits

TL;DR

This paper presents a straightforward all-microwave entangling gate for fixed-frequency superconducting qubits, achieving high entanglement and fidelity without extra circuitry, simplifying quantum processor design.

Contribution

It introduces a novel microwave-based two-qubit gate that operates on fixed-frequency qubits without additional hardware, enhancing scalability and simplicity.

Findings

Maximal concurrence of 0.88 in entangled states

Gate fidelity of 81% from quantum process tomography

No additional subcircuitry needed for the gate

Abstract

We demonstrate an all-microwave two-qubit gate on superconducting qubits which are fixed in frequency at optimal bias points. The gate requires no additional subcircuitry and is tunable via the amplitude of microwave irradiation on one qubit at the transition frequency of the other. We use the gate to generate entangled states with a maximal extracted concurrence of 0.88 and quantum process tomography reveals a gate fidelity of 81%.