Optimal model for fewer-qubit CNOT gates with Rydberg atoms

TL;DR

This paper presents an optimized method for implementing fewer-qubit CNOT gates using Rydberg atoms, reducing errors and operation time through global pulse optimization and simultaneous excitation.

Contribution

It introduces a novel optimal model for two- and three-qubit CNOT gates mediated by Rydberg states, utilizing genetic algorithms for pulse optimization to improve efficiency and fidelity.

Findings

Achieves 99.23% fidelity for two-qubit CNOT gate at 7.10 μm separation.

Reduces multi-pulse switching time by enabling simultaneous excitation.

Demonstrates potential for fast, reliable multiqubit quantum gates with Rydberg atoms.

Abstract

Fewer-qubit quantum logic gate, serving as a basic unit for constructing universal multiqubit gates, has been widely applied in quantum computing and quantum information. However, traditional constructions for fewer-qubit gates often utilize a multi-pulse protocol which inevitably suffers from serious intrinsic errors during the gate execution. In this article, we report an optimal model about universal two- and three-qubit CNOT gates mediated by excitation to Rydberg states with easily-accessible van der Waals interactions. This gate depends on a global optimization to implement amplitude and phase modulated pulses via genetic algorithm, which can facilitate the gate operation with fewer optical pulses. Compared to conventional multi-pulse piecewise schemes, our gate can be realized by simultaneous excitation of atoms to the Rydberg states, saving the time for multi-pulse switching at different spatial locations. Our numerical simulations show that a single-pulse two(three)-qubit CNOT gate is possibly achieved with a fidelity of 99.23$\%$(90.39$\%$) for two qubits separated by 7.10 $\mu$m when the fluctuation of Rydberg interactions is excluded. Our work is promising for achieving fast and convenient multiqubit quantum computing in the study of neutral-atom quantum technology.