# Optimized cavity-mediated dispersive two-qubit gates between spin qubits

## TL;DR

This paper proposes an optimized cavity-mediated two-qubit gate for spin qubits in silicon, achieving high fidelities exceeding 90% by balancing spin-charge hybridization and mitigating decoherence effects.

## Contribution

It introduces a method to optimize spin-charge hybridization for cavity-mediated two-qubit gates, enhancing fidelity in silicon quantum dot systems.

## Key findings

- Gate fidelities exceeding 90% are achievable with current device architectures.
- High fidelities are maintained even with charge noise at 2 μeV.
- Optimization of hybridization improves entangling gate performance.

## Abstract

The recent realization of a coherent interface between a single electron in a silicon quantum dot and a single photon trapped in a superconducting cavity opens the way for implementing photon-mediated two-qubit entangling gates. In order to couple a spin to the cavity electric field some type of spin-charge hybridization is needed, which impacts spin control and coherence. In this work we propose a cavity-mediated two-qubit gate and calculate cavity-mediated entangling gate fidelities in the dispersive regime, accounting for errors due to the spin-charge hybridization, as well as photon- and phonon-induced decays. By optimizing the degree of spin-charge hybridization, we show that two-qubit gates mediated by cavity photons are capable of reaching fidelities exceeding 90% in present-day device architectures. High iSWAP gate fidelities are achievable even in the presence of charge noise at the level of $2\,\mu\text{eV}$.