Rydberg Entangling Gates in Silicon

Abstract

Spin qubits of donors in silicon show some of the longest coherence times recorded and hold the promise of scalability with seamless integration of quantum computing into semiconductor fabrication. However, current entangling gate implementations rely on highly challenging precision donor placement and substantial gate tuning, rendering scaling challenging. In this work, we show how to implement placement-insensitive ultrafast entangling gates in deep and shallow donors in silicon by relying on the Rydberg blockade induced by strong interactions between low lying orbital excited states. We calculate multivalley interactions for several donor species using the Finite Element Method, and show that Van der Waals interactions between donors, calculated here for the first time, are important even for low-lying excited states. We show that blockade entangling gate operation is possible within the short lifetime of donor excited states with over 99% fidelity for the creation of a Bell state in the presence of decoherence. This gate substantially relaxes the requirements on single donor placement while allowing for billions of entangling gate operations within the single-qubit lifetime, thus paving the way for large scale quantum computation in silicon.

A concise review of Rydberg atom based quantum computation and quantum simulation*

“…[131] In the past few years, tremendous amount of theoretical studies on Rydberg gates lead to the development of many other schemes, aimed at improving the performance of Rydberg mediated quantum gates. One plausible route towards this goal is to go beyond the simple blockade proposal by designing novel pulse sequences such as parallel laser driving with a phase jump, [132,133] or by engineering intrinsic interaction mechanisms such as employing Stark-tuned Förster resonance [134][135][136] and microwave dressing. [78][79][80] Alternatively, by using shaped pulses [137,138] and adiabatic passages, [139][140][141][142][143][144][145] one can build up high-fidelity Rydberg gates that are robust against control errors.…”