Off-resonant modulated driving gate protocols for two-photon ground-Rydberg transition and finite Rydberg blockade strength

TL;DR

This paper analyzes off-resonant modulated driving protocols for two-photon ground-Rydberg transitions, demonstrating improved performance and reduced blockade strength requirements, which enhance qubit connectivity and fidelity in neutral atom quantum computing.

Contribution

It introduces a comprehensive analysis of modulation styles for two-photon transitions and refines protocol design for finite Rydberg blockade strengths, improving practical quantum gate performance.

Findings

Versatile modulation styles demonstrated for two-photon transitions.

Refined protocols enable high fidelity even with weaker Rydberg blockade.

Potential for near-term experimental implementation with current technology.

Abstract

Recently, the notion of two-qubit controlled phase gate via off-resonant modulated driving has been introduced into the neutral atom qubit platform, with respect to both single-photon and two-photon ground-Rydberg transitions. In order to reach a better performance practically, further developments are in need to overcome a few known limitations in previous discussions of this promising method. Here, we thoroughly analyze a variety of modulation styles for two-photon transitions, demonstrating the versatility of off-resonant modulated driving protocols. Furthermore, we show that it is possible to refine the designing process for improved performances for specific finite Rydberg blockade strength values. In particular, a reduced requirement on the blockade strength can be directly linked to an improvement of connectivity in qubit array of neutral atoms. These progress are closely related to the core feature that the atomic wave function acquires a geometric phase from the time evolution, which begins and finishes at the same quantum state. Under reasonable experimental conditions readily available nowadays, we anticipate that the fidelity of such protocols can reach as high as the essential requirement of NISQ even if the effects of technical errors and cold atoms' nonzero temperatures are considered.