Fast, Accurate, and Realizable Two-Qubit Entangling Gates by Quantum Interference in Detuned Rabi Cycles of Rydberg Atoms

Abstract

High-fidelity entangling quantum gates based on Rydberg interactions are required for scalable quantum computing with neutral atoms. Their realization, however, meets a major stumbling block -- the motion-induced dephasing of the transition between the ground and Rydberg states. By using quantum interference between different detuned Rabi oscillations, we propose a practical scheme to realize a class of accurate entangling Rydberg quantum gates subject to a minimal dephasing error. We show two types of such gates, $U_1$ and $U_2$, in the form of $\text{diag}\{1,e^{i\alpha },e^{i\gamma },e^{i\beta }\}$, where $\alpha ,\gamma$, and $\beta$ are determined by the parameters of lasers and the Rydberg blockade $V$. $U_1$ is realized by sending to the two qubits a single off-resonant laser pulse, while $U_2$ is realized by individually applying one pulse of detuned laser to each qubit. Our method has several advantages. First, the gates are accurate because the fidelity of $U_k$ is limited only by a rotation error below $10^{-5}$ and the Rydberg-state decay. Decay error on the order of $10^{-5}$ can be easily obtained because all transitions are detuned, resulting in small population in Rydberg state. Second, the motion-induced dephasing is minimized because there is no gap time in which a population is left in the Rydberg shelving states of either qubit. Third, the gate is resilient to the variation of $V$. This is because among the three phases $\alpha ,\gamma$, and $\beta$, only the last has a (partial) dependence on $V$. Fourth, the Rabi frequency and $V$ in our scheme are of similar magnitude, which permits a fast implementation of the gate when both of them are of the feasible magnitude of several megahertz. The rapidity, accuracy, and feasibility of this interference method can lay the foundation for entangling gates in universal quantum computing with neutral atoms.

Version 2 (19 pages, 10 figures) studies the first type of gate with smaller Rabi frequencies. Version 1 studies the second type of gate with larger Rabi frequencies. Full text can be downloaded by first clicking the title of this work at the site (https://faculty.xidian.edu.cn/SXF/en/lwcg/389995/list/index.htm) and then locating the pdf item

References in corpus (20)

• QuTiP 2: A Python framework for the dynamics of open quantum systems
• An atom-by-atom assembler of defect-free arbitrary 2d atomic arrays
• High-fidelity control and entanglement of Rydberg atom qubits
• Quasiclassical calculations of BBR-induced depopulation rates and effective lifetimes of Rydberg nS, nP and nD alkali-metal atoms with n < 80
• Fidelity of quantum operations
• Consequences of Zeeman Degeneracy for van der Waals Blockade between Rydberg Atoms
• Coherent Excitation Transfer in a Spin Chain of Three Rydberg Atoms
• Cooling a single atom in an optical tweezer to its quantum ground state
• Analysis of imperfections in the coherent optical excitation of single atoms to Rydberg states
• Deterministic entanglement of two neutral atoms via Rydberg blockade
• High-fidelity Rydberg quantum gate via a two-atom dark state
• Local optical control of the resonant dipole-dipole interaction between Rydberg atoms
• Phase shift of a weak coherent beam induced by a single atom
• Deutsch, Toffoli, and CNOT Gates via Rydberg Blockade of Neutral Atoms
• Unconventional Rydberg pumping and applications in quantum information processing
• Fast three-qubit Toffoli quantum gate based on the three-body Förster resonances in Rydberg atoms
• Adiabatic passage of radiofrequency-assisted Forster resonances in Rydberg atoms for two-qubit gates and generation of Bell states
• Accurate Quantum Logic Gates by Spin Echo in Rydberg Atoms
• Entanglement of neutral-atom chains by spin-exchange Rydberg interaction
• Universal Barenco quantum gates via a tunable non-collinear interaction

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• Suppress motional dephasing of ground-Rydberg transition for high-fidelity quantum control with neutral atoms
• Doppler-resilient ground-Rydberg transition and its application in high-fidelity entangling gates with neutral atoms
• Application of adiabatic passage in Rydberg atomic ensembles for quantum information processing
• Effective Rabi dynamics of Rydberg atoms and robust high-fidelity quantum gates with a resonant amplitude-modulation field
• Single temporal-pulse-modulated parameterized controlled-phase gate for Rydberg atoms
• Dipole-dipole interaction driven antiblockade of two Rydberg atoms
• Scalable $W$-type entanglement resource in neutral-atom arrays with Rydberg-dressed resonant dipole-dipole interaction
• Unselective ground-state blockade of Rydberg atoms for implementing quantum gates
• Dynamical generation of chiral $W$ and Greenberger-Horne-Zeilinger states in laser-controlled Rydberg-atom trimers
• Transition Slow-Down by Rydberg Interaction of Neutral Atoms and a Fast Controlled-NOT Quantum Gate
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• Hyperentanglement of divalent neutral atoms by Rydberg blockade
• High-fidelity Rydberg controlled-Z gates with optimal pulses
• Single-site Rydberg addressing in 3D atomic arrays for quantum computing with neutral atoms
• Quantum gates with weak van der Waals interactions of neutral Rydberg atoms
• Simulation of a feedback-based algorithm for quantum optimization for a realistic neutral atom system with an optimized small-angle controlled-phase gate
• Fast nuclear-spin gates and electrons-nuclei entanglement of neutral atoms in weak magnetic fields
• Fast nuclear-spin entangling gates compatible with large-scale atomic arrays
• Physical swap dynamics, shortcuts to relaxation and entropy production in dissipative Rydberg gases
• One-step preparation of 3D Bell and 3D GHZ states with Rydberg atoms
• Fast measurement-based generation of large-scale Greenberger-Horne-Zeilinger state with atomic nuclear-spin qubits