Can the gate time of Rydberg two-qubit gate be shorten by increasing the strength of Rydberg interaction?

TL;DR

This paper investigates how the strength of Rydberg interactions influences the speed of two-qubit gates in atomic arrays, revealing that weak interactions can enable faster gate operations than the Rydberg blockade regime.

Contribution

It demonstrates that increasing Rydberg interaction strength does not shorten gate time in the blockade regime, but weak interactions can accelerate gates via geometric control.

Findings

Gate time is independent of Rydberg interaction strength in blockade regime.

Weak Rydberg interactions can enable faster two-qubit gates.

Fast and robust gates are achievable with geometric control in weak interaction regimes.

Abstract

In this manuscript we discuss the relationship between the gate time of Rydberg two-qubit gate and the Rydberg interaction strength. Different from the two-qbuit gates that directly depend on the interactions between the spins (or pseudo spins), the ones in atomic arrays are realized by driving the atoms to the Rydberg states. As a consequence, competition happens between shortening the gate time and decreasing the excitation probability of Rydberg states. For the case of Rydberg blockade, it is found that the gate time is irrelevant of the Rydberg interaction strength. In contrast, for the case of weak Rydberg interactions, the interactions will help to accelerate the two-qubit gates. This implies that the scheme of weak Rydberg interactions will be faster than the Rydberg blockade one to realize the two-qbuit gates under the same Rabi frequencies of Rydberg excitation. Through using the geometric control under the region of weak Rydberg interaction, fast and robust two-qubit gates can be achieved in atomic arrays, of which detailed discussion can be referred to the manuscript \textsl{arXiv:2412. 19193 (2024)}.