Fast and robust entanglement using Rydberg atoms

Xiaofeng Shi

Lucas Béguin, Aline Vernier, Radu Chicireanu +2 more

Jin‐Lei Wu, Yan Wang, Jin‐Xuan Han +4 more

Abstract The idea of periodic pulse engineering (PPE) is exploited to achieve unconventional Rydberg pumping for a robust multiqubit gate on Rydberg atoms trapped in a 2D array. By designing component parameters in PPE, fast regimes of full and partial Rydberg antiblockade (RAB) among three atoms are explored. Furthermore, through assigning appropriate components in PPE a phenomenon of RAB‐based blockade emerges and then a three‐qubit gate can be achieved. It is identified that two kinds of Rydberg–Rydberg interaction (RRI), van der Waals interaction and dipole–dipole Förster resonance interaction, are both applicative for implementing the proposed scheme. Different from recent schemes of Rydberg atom multiqubit gates, the operated atoms are indistinguishable with respect to the laser field of PPE, and the present one‐step scheme is essentially fast owing to the first‐order dynamics where the dominant component in PPE is not degraded. In addition, the proposed multiqubit gate is robust against atomic decay and deviation of RRI strengths, because the excitation duration of atoms is short, with the total excitation number ⩽1. This work may facilitate experimental demonstration of RAB‐based gates of strongly coupled atoms.

Alpha Gaétan, Charles Evellin, Y. Miroshnychenko +8 more

Giuliano Giudici, Stefano Veroni, Giacomo Giudice +2 more

The advent of digital neutral-atom quantum computers relies on the development of fast and robust protocols for high-fidelity quantum operations. In this work, we introduce a novel scheme for entangling gates using four atomic levels per atom: a ground-state qubit and two Rydberg states. A laser field couples the qubit to one of the two Rydberg states, while a microwave field drives transitions between the two Rydberg states, enabling a resonant dipole-dipole interaction between different atoms. We show that controlled- Z gates can be realized in this scheme without requiring optical phase modulation and relying solely on a microwave field with time-dependent phase and amplitude. We demonstrate that such gates are faster and less sensitive to Rydberg decay than state-of-the-art Rydberg gates based on van der Waals interactions. Moreover, we systematically stabilize our protocol against interatomic distance fluctuations and analyze its performance in realistic setups with rubidium or cesium atoms. Our results open up new avenues to the use of microwave-driven dipolar interactions for quantum computation with neutral atoms.

Antoine Browaeys, Alpha Gaétan, Charles Evellin +8 more