Overcoming Stark-Shift Constraints in Phase-Controlled Rydberg Two-Qubit Gates

TL;DR

This paper presents methods to overcome Stark-shift limitations in Rydberg two-qubit gates, enabling high-fidelity entangling gates through phase and amplitude control with optimized pulse sequences.

Contribution

It introduces two robust control schemes that allow arbitrary two-qubit phase gates with high fidelity, overcoming Stark-shift constraints in Rydberg systems.

Findings

High-fidelity two-qubit phase gates achieved

Robust control schemes tailored for different phase gates

Effective pulse sequences of even or odd length

Abstract

Stark shifts introduce additional phases that constrain the set of entangling gates that can be prepared via two-photon transitions in the strong Rydberg blockade limit. For non-independently addressed qubits, by controlling the absolute phases and the local amplitudes of the pulses at each qubit, we show that any two-qubit phase gate can be prepared with high fidelity using a three-pulse sequence. Based on these insights, we introduce two robust control schemes tailored to different phase gates that yield better results with pulse sequences of either even or odd length.