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arXiv:2504.15282 · Physical Review Research

Multitarget Rydberg gates via spatial blockade engineering

Samuel Stein, Chenxu Liu, Shuwen Kan, Eleanor Crane, Yufei Ding, Ying Mao, Alexander Schuckert, Ang Li

Published Jan 23, 2026• 3 citations
arXivHTMLPDF

Abstract

Multitarget gates offer the potential to reduce gate depth in syndrome extraction for quantum error correction. Although neutral-atom quantum computers have demonstrated native multiqubit gates, existing approaches that avoid additional control or multiple atomic species have been limited to single-target gates. We propose single-control multitarget C ( Z ⊗ N ) gates on a single-species neutral-atom platform that requires no extra control and has gate durations comparable to standard C Z gates. Our approach leverages tailored interatomic distances to create an asymmetric blockade between the control and target atoms. Using a graphics processing unit-accelerated pulse synthesis protocol, we design smooth control pulses for C Z Z and C Z Z Z gates, achieving fidelities of up to 99.55 % and 99.24 % , respectively, even in the presence of simulated atom-placement errors and Rydberg-state decay. Our approach is most effective for N = 2 ( C Z Z ) and N = 3 targets ( C Z Z Z ) ; for larger , increasing spatial crowding of the targets introduces significant challenges for maintaining the required blockade asymmetry. This work presents a practical path to implementing low-overhead multitarget gates in single-species neutral-atom systems, significantly reducing the resource overhead for syndrome extraction. To motivate the impact of these gates, we apply a greedy scheduling algorithm and we demonstrate that our proposed gates can reduce the number of atom reconfiguration costs by up to 50% for color code syndrome extraction of code distances greater than 5.

DOI
10.1103/k72m-9tn8

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Multitarget gates offer the potential to reduce gate depth in syndrome extraction for quantum error correction. Although neutral-atom quantum computers have demonstrated native multiqubit gates, existing approaches that avoid additional control or multiple atomic species have been limited to single-target gates. We propose single-control multitarget C ( Z ⊗ N ) gates on a single-species neutral-atom platform that requires no extra control and has gate durations comparable to standard C Z gates. Our approach leverages tailored interatomic distances to create an asymmetric blockade between the control and target atoms. Using a graphics processing unit-accelerated pulse synthesis protocol, we design smooth control pulses for C Z Z and C Z Z Z gates, achieving fidelities of up to 99.55 % and 99.24 % , respectively, even in the presence of simulated atom-placement errors and Rydberg-state decay. Our approach is most effective for N = 2 ( C Z Z ) and N = 3 targets ( C Z Z Z ) ; for larger , increasing spatial crowding of the targets introduces significant challenges for maintaining the required blockade asymmetry. This work presents a practical path to implementing low-overhead multitarget gates in single-species neutral-atom systems, significantly reducing the resource overhead for syndrome extraction. To motivate the impact of these gates, we apply a greedy scheduling algorithm and we demonstrate that our proposed gates can reduce the number of atom reconfiguration costs by up to 50% for color code syndrome extraction of code distances greater than 5.
Due to its potential for implementing a scalable quantum computer, the multiqubit Toffoli gate lies in the heart of quantum information processing. In this paper, we demonstrate a multiqubit blockade gate with atoms arranged in a three-dimensional spheroidal array. The gate performance is greatly improved by the method of optimizing control-qubit distributions on the spherical surface via evolutionary algorithm, which leads to an enhanced asymmetric Rydberg blockade. This spheroidal configuration, not only preserves the dipole blockade energy well between arbitrary control-target pairs, which keeps the asymmetric blockade error at a very low level, but also manifests an unprecedented robustness to the spatial position variations, leading to a negligible position error. Taking account of intrinsic errors and using typical experimental parameters, we numerically show that a c6{}_{6}6​not Rydberg gate can be created with a fidelity of 0.992, which is only limited by the Rydberg state decays. Our protocol opens up a platform of higher-dimensional atomic arrays for achieving multiqubit neutral-atom quantum computation.
A clever choice and design of gate sets can reduce the depth of a quantum circuit, and can improve the quality of the solution one obtains from a quantum algorithm. This is especially important for near-term quantum computers that suffer from various sources of error that propagate with the circuit depth. Parametrized gates in particular have found use in both near-term algorithms and circuit compilation. The one- and two-qubit versions of these gates have been demonstrated on various computing architectures. The neutral-atom platform has the capability to implement native NNN-qubit gates (for $N\ensuremath{\ge}2$). However, one needs to first find the control functions that implement these gates on the hardware. We study the numerical optimization of neural networks towards obtaining families of controls---laser pulses to excite an atom to Rydberg states---that implement phase gates with one and two controls, the C1P{\mathrm{C}}_{1}\phantom{\rule{-0.1em}{0ex}}\mathrm{P}C1​P and C2P{\mathrm{C}}_{2}\phantom{\rule{-0.1em}{0ex}}\mathrm{P}C2​P gates, respectively, on neutral-atom hardware. The pulses we obtain have a duration significantly shorter than the loss time scale, set by decay from the Rydberg state. In addition, they do not require single-site addressability and are smooth. Hence, we expect our gates to have immediate benefits for quantum algorithms implemented on current neutral-atom hardware.
Multiqubit gates that involve three or more qubits are usually thought to be of little significance for fault-tolerant quantum error correction because single gate faults can lead to errors of high Pauli weight. However, recent works have shown that multiqubit gates can be beneficial for measurement-free fault-tolerant quantum error correction and for fault-tolerant stabilizer readout in unrotated surface codes. In this work, we investigate multiqubit Rydberg gates that are useful for fault-tolerant quantum error correction in single-species neutral-atom platforms and can be implemented with global laser pulses that do not individually address atomic sites. We develop an open-source Python package to generate analytical, few-parameter pulses that implement the desired gates while minimizing gate errors due to Rydberg-state decay. The tool also allows us to identify parameter-optimal pulses, characterized by a minimal parameter count for the pulse ansatz. Measurement-free quantum error correction protocols require CCZ gates, which we analyze for atoms arranged in symmetric and asymmetric configurations. We investigate the performance of these schemes for various single-, two-, and three-qubit gate error rates, showing that break-even performance of measurement-free QEC is within reach of current hardware. Moreover, we study Floquet quantum error correction protocols that comprise two-body stabilizer measurements. Those can be realized using global three-qubit gates, and we show that this can lead to a significant reduction in shuttling operations. Simulations with realistic circuit-level noise indicate that applying three-qubit gates for stabilizer measurements in Floquet codes can yield competitive logical qubit performance in experimentally relevant error regimes.
A clever choice and design of gate sets can reduce the depth of a quantum circuit, and can improve the quality of the solution one obtains from a quantum algorithm. This is especially important for near-term quantum computers that suffer from various sources of error that propagate with the circuit depth. Parametrized gates in particular have found use in both near-term algorithms and circuit compilation. The one- and two-qubit versions of these gates have been demonstrated on various computing architectures. The neutral atom platform has the capability to implement native NNN-qubit gates (for N≥2N \geq 2N≥2). However, one needs to first find the control functions that implement these gates on the hardware. We study the numerical optimization of neural networks towards obtaining families of controls −-− laser pulses to excite an atom to Rydberg states −-− that implement phase gates with one and two controls, the C1P\mathrm{C_1P}C1​P and C2P\mathrm{C_2P}C2​P gates respectively, on neutral atom hardware. The pulses we obtain have a duration significantly shorter than the loss time scale, set by decay from the Rydberg state. Further, they do not require single-site addressability and are smooth. Hence, we expect our gates to have immediate benefits for quantum algorithms implemented on current neutral atom hardware.
We present a native approach for realizing multiqubit parity phase gates in neutral-atom systems through global phase modulation of a Rydberg excitation laser. By shaping the temporal profile of the laser’s phase, we enable high-fidelity, time efficient entangling operations between multiple qubits without requiring individual qubit addressing. To mitigate intrinsic noise sources including spontaneous decay and motional effects, we develop a noise-aware optimal control framework that reduces gate errors under the presence of noise while maintaining smooth pulse profiles suitable for experimental implementation. In addition to equidistant qubit arrangements, we explore the impact of nonequidistant atomic configurations, where interaction inhomogeneity becomes significant. In these cases, the flexibility of our control approach helps to compensate for such variations, supporting reliable gate performance across different spatial layouts. These results facilitate the practical implementation of complex, multiqubit quantum operations in near-term neutral-atom quantum processors.
Quantum error correction (QEC) requires the execution of deep quantum circuits with large numbers of physical qubits to protect information against errors. Designing protocols that can reduce gate and space-time overheads of QEC is therefore crucial to enable more efficient QEC in near-term experiments. Multiqubit gates offer a natural path toward fast and low-depth stabilizer measurement circuits. However, they typically introduce high-weight correlated errors that can degrade the circuit-level distance, leading to slower scalings of the logical error probabilities. In this Letter, we show how to realize fast and efficient surface code stabilizer readout using only two singly controlled z gates acting simultaneously on two target qubits, i.e., two CZ_{2} gates-instead of four cz. We show that this scheme is fault tolerant and provide a blueprint for implementation in Rydberg atom arrays. We derive the time-optimal pulses implementing the gates and perform extensive QEC numerical simulations with Rydberg decay errors. Compared to the standard protocol using four cz gates, our scheme is faster, uses fewer gates, and crucially maintains fault tolerance with comparable logical error probabilities. Fault-tolerant generalizations of this scheme to biased and erasure-dominant noise models, as well as to other QEC codes such as quantum Low-Density Parity-Check codes, are also discussed.