Robust Rydberg gate via Landau-Zener control of F\"orster resonance

TL;DR

This paper introduces a robust two-qubit controlled-Z gate scheme using Landau-Zener control of F"orster resonance in Rydberg atoms, demonstrating high fidelity and insensitivity to fluctuations, feasible with current experimental technology.

Contribution

It presents a novel Landau-Zener control method for implementing a robust Rydberg-based controlled-Z gate with enhanced stability against parameter fluctuations.

Findings

Gate fidelity is insensitive to interaction time fluctuations.

The scheme is feasible with current Cs atom experimental setups.

Population and phase are quasi-deterministic after cyclic evolution.

Abstract

In this paper, we propose a scheme to implement the two-qubit controlled-Z gate via the Stark-tuned F\"orster interaction of Rydberg atoms, where the F\"orster defect is driven by a time-dependent electric field of a simple sinusoidal function while the matrix elements of the dipole-dipole interaction are time-independent. It is shown that when the system is initially in a specific state, it makes a cyclic evolution after a preset interaction time, returning to the initial state, but picks up a phase, which can be used for realizing a two-atom controlled-Z gate. Due to the interference of sequential Landau-Zener transitions, the population and phase of the state is quasi-deterministic after the cyclic evolution and therefore the gate fidelity is insensitive to fluctuations of the interaction time and the dipole-dipole matrix elements. Feasibility of the scheme realized with Cs atoms is discussed in detail, which shows that the two-qubit gate via Landau-Zener control can be realized with the state-of-the-art experimental setup.