# Demonstration of a Parametrically-Activated Entangling Gate Protected from Flux Noise

## TL;DR

This paper experimentally validates a flux-noise protected parametric entangling gate in superconducting qubits, achieving high fidelity and demonstrating robustness against flux noise and electronic noise.

## Contribution

It provides the first experimental validation of the AC sweet spot for a parametric entangling gate, enhancing gate fidelity and noise resilience.

## Key findings

- Achieved entangling gate fidelity of 99.2%.
- Validated the existence of the AC sweet spot.
- Demonstrated dependence of gate performance on electronic noise.

## Abstract

In state-of-the-art quantum computing platforms, including superconducting qubits and trapped ions, imperfections in the 2-qubit entangling gates are the dominant contributions of error to system-wide performance. Recently, a novel 2-qubit parametric gate was proposed and demonstrated with superconducting transmon qubits. This gate is activated through RF modulation of the transmon frequency and can be operated at an amplitude where the performance is first-order insensitive to flux-noise. In this work we experimentally validate the existence of this AC sweet spot and demonstrate its dependence on white noise power from room temperature electronics. With these factors in place, we measure coherence-limited entangling-gate fidelities as high as 99.2 $\pm$ 0.15%.