Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2312.06327 · Physical Review A

Fast nuclear-spin entangling gates compatible with large-scale atomic arrays

Xiaofeng Shi, Yan Lü

Published Jul 12, 2024• 3 citations
arXivHTMLPDF

Abstract

Fast nuclear-spin entangling gates of divalent atoms can be realized with one global laser pulse when ${\mathrm{\ensuremath{\Delta}}}_{\text{Z}}<\mathrm{\ensuremath{\Omega}}$, where ${\mathrm{\ensuremath{\Delta}}}_{\text{Z}}$ is the Zeeman-splitting-dominated frequency difference between the two clock-Rydberg transitions of the two qubit states and $\mathrm{\ensuremath{\Omega}}$ is the maximal Rabi frequency. The condition ${\mathrm{\ensuremath{\Delta}}}_{\text{Z}}<\mathrm{\ensuremath{\Omega}}$ and the sensitivity of Rydberg-state energy to magnetic fluctuation demand the magnetic field to be weak, making the gate compatible with large-scale atomic arrays because weaker magnetic fields can be smoother in a large qubit array. The gate can have a high fidelity for the decoherence of Rydberg states, which limits the gate fidelity and grows with $1/\mathrm{\ensuremath{\Omega}}$, can be mitigated with easily attainable large $\mathrm{\ensuremath{\Omega}}$.

DOI
10.1103/physreva.110.012610

Related papers

Fast nuclear-spin gates and electrons-nuclei entanglement of neutral atoms in weak magnetic fields

Xiaofeng Shi

We present a novel class of Rydberg-mediated nuclear-spin entanglement in divalent atoms with global laser pulses. First, we show a fast nuclear-spin controlled phase gate of an arbitrary phase realizable either with two laser pulses when assisted by Stark shifts, or with three pulses. Second, we propose to create an electrons–nuclei-entangled state, which is named a super bell state (SBS) for it mimics a large Bell state incorporating three small Bell states. Third, we show a protocol to create a three-atom electrons-nuclei entangled state which contains the three-body W and Green-berger–Horne–Zeilinger (GHZ) states simultaneously. These protocols possess high intrinsic fidelities, do not require single-site Rydberg addressing, and can be executed with large Rydberg Rabi frequencies in a weak, Gauss-scale magnetic field. The latter two protocols can enable measurement-based preparation of Bell, hyperentangled, and GHZ states, and, specifically, SBS can enable quantum dense coding where one can share three classical bits of information by sending one particle.

arXiv:2212.05876•Frontiers of Physics•Dec 7, 2023•4 citations

Accurate Quantum Logic Gates by Spin Echo in Rydberg Atoms

Xiaofeng Shi

Implementation of accurate quantum gates based on Rydberg interactions is required for scalable quantum computing with ultracold neutral atoms, but has been held back by the difficulty of realizing high-fidelity two-qubit Rydberg gates. This study proposes an easily realizable controlled-$Z$ gate of high intrinsic fidelity, based on spin echo in Rydberg atoms. The ability to attain an accurate entangling Rydberg gate, with neither pulse shaping nor atomic vibrational-ground-state cooling, makes ultracold atoms promising for large-scale quantum computing.

arXiv:1809.01758•Physical Review Applied•Sep 5, 2018•28 citations

Optimized ancillary drive for fast Rydberg entangling gates

Rui Li, Min-Hua Zhang, Jing Qian

Reaching fast and robust two-qubit gates with low infidelities has been an outstanding challenge for the long-term goal of useful quantum computers. Typically, optimizing the pulse shapes can minimize the gate infidelity and improve its robustness to certain types of errors; yet it remains incapable of speeding up the gate execution time which is fundamentally restricted by the attainable Rabi frequency in a realistic setup. In this work, we develop a fast implementation of two-qubit CZ gates using optimized ancillary drive to enhance the two-photon Rabi frequency between the ground and Rydberg states.This ancillary drive can work in an error-robustness framework without increasing the original gate infidelity in the absence of the drive. Considering the experimentally feasible parameters for $^{87}$Rb atoms, we demonstrate that the execution time required for such CZ gates can be shortened by more than 30$\%$ as compared to standard two-photon protocols arising the gate fidelity above 0.9954 by taking account of all relevant error sources. Our results reduce the high-power laser requirement and unlock the potential toward fast, high-fidelity quantum operations for large-scale quantum computation with neutral atoms.

quant-pharXiv:2602.21512•Feb 26, 2026•0 citations

Neutral-atom entanglement using adiabatic Rydberg dressing

Anupam Mitra, Sivaprasad Omanakuttan, Michael J. Martin +2 more

We revisit the implementation of a two-qubit entangling gate, the M\o{}lmer-S\o{}rensen gate, using the adiabatic Rydberg dressing paradigm for neutral atoms as studied in [A. Mitra et al., Phys. Rev. A 101, 030301(R) (2020)]. We study the implementation of rapid adiabatic passage using a two-photon transition, which does not require the use of an ultraviolet laser, and can be implemented using only amplitude modulation of one field with all laser frequencies fixed. We find that entangling gate fidelities, comparable to the one-photon excitation, are achievable with the two-photon excitation. Moreover, we address how the adiabatic dressing protocol can be used to implement entangling gates outside the regime of a perfect Rydberg blockade. We show that, by using adiabatic dressing, we can achieve scaling of the gate fidelity set by the fundamental limits to entanglement generated by the Rydberg interactions while simultaneously retaining a limited population in the doubly excited Rydberg state. This allows for fast high-fidelity gates for atoms separated beyond the blockade radius.

arXiv:2205.12866•Physical Review A•Jun 15, 2023•19 citations

High-Fidelity Universal Quantum Gates in a Cryogenic Atom Array

Junlan Jin, Donghyuk Seo, Yue Shi +3 more

Neutral atoms in optical tweezer arrays have emerged as a leading platform for quantum information processing. The fidelity of entangling gates mediated by Rydberg interactions has improved rapidly and is increasingly constrained by blackbody-radiation-induced transitions, which shorten Rydberg lifetimes and create contaminant states that can cause correlated errors. Cryogenic environments can suppress these transition rates by more than an order of magnitude. However, realizing a universal gate set in such an environment has remained an outstanding challenge. Here, we demonstrate a universal quantum gate set in a cryogenic $^{133}$Cs atom array, with a single-qubit gate fidelity of 99.970(2)% and a raw two-qubit entangling-gate fidelity of 99.76(8)%, within the range of leading room-temperature implementations. The entangling gate uses direct single-photon coupling between the electronic ground state and a Rydberg $P$ state, avoiding scattering and light shifts associated with two-photon coupling. The gate operates at a modest Rabi frequency of $2π\times4.3$ MHz. The measured fidelity agrees with our error model dominated by atomic motion, indicating a straightforward route to higher fidelity through improved cooling, while the fundamental error contribution from Rydberg decay is below $3\times10^{-4}$. These results establish a path to entangling-gate fidelities substantially beyond the current state of the art through cryogenic suppression of Rydberg decay, reducing the overhead for fault-tolerant computation.

physics.atom-phCross-listedarXiv:2610.40329•Oct 30, 2026•0 citations

Detuning-robust Rydberg entangling gates from echoed pulses

Zhubing Jia, Yichao Yu, Xiye Hu +4 more

Rydberg-based two-qubit gate fidelities in neutral atom arrays are limited chiefly by laser intensity inhomogeneity and by detuning errors from frequency miscalibration, background-field drift, intermediate state light shift and Doppler shifts. Quantum optimal control can suppress the former, but no pulse can render a controlled-Z gate first-order insensitive to detuning. Here we show that this obstruction can be circumvented by designing Rydberg gate pulses with every leading-order detuning error relegated to single-qubit Z-rotations, which an echoed sequence removes. The resulting maximally-entangling ZZ gate has no leading-order response to arbitrary detunings on either atom, maintaining an infidelity below $10^{-3}$ within a much wider range of single-atom detunings than the time-optimal gates. We further show that a large fraction of residual error is dominated by population outside the computational subspace, which can be converted into heralded erasures. Our results significantly reduce the requirements on laser frequency stability and intensity homogeneity, field calibration and atomic temperature toward practical fault-tolerant quantum computing with neutral atoms.

quant-pharXiv:2608.26446•Aug 28, 2026•0 citations
Fast nuclear-spin entangling gates of divalent atoms can be realized with one global laser pulse when \ensuremathΔZ<\ensuremathΩ{\mathrm{\ensuremath{\Delta}}}_{\text{Z}}<\mathrm{\ensuremath{\Omega}}\ensuremathΔZ​<\ensuremathΩ, where \ensuremathΔZ{\mathrm{\ensuremath{\Delta}}}_{\text{Z}}\ensuremathΔZ​ is the Zeeman-splitting-dominated frequency difference between the two clock-Rydberg transitions of the two qubit states and \ensuremathΩ\mathrm{\ensuremath{\Omega}}\ensuremathΩ is the maximal Rabi frequency. The condition \ensuremathΔZ<\ensuremathΩ{\mathrm{\ensuremath{\Delta}}}_{\text{Z}}<\mathrm{\ensuremath{\Omega}}\ensuremathΔZ​<\ensuremathΩ and the sensitivity of Rydberg-state energy to magnetic fluctuation demand the magnetic field to be weak, making the gate compatible with large-scale atomic arrays because weaker magnetic fields can be smoother in a large qubit array. The gate can have a high fidelity for the decoherence of Rydberg states, which limits the gate fidelity and grows with 1/\ensuremathΩ1/\mathrm{\ensuremath{\Omega}}1/\ensuremathΩ, can be mitigated with easily attainable large \ensuremathΩ\mathrm{\ensuremath{\Omega}}\ensuremathΩ.
We present a novel class of Rydberg-mediated nuclear-spin entanglement in divalent atoms with global laser pulses. First, we show a fast nuclear-spin controlled phase gate of an arbitrary phase realizable either with two laser pulses when assisted by Stark shifts, or with three pulses. Second, we propose to create an electrons–nuclei-entangled state, which is named a super bell state (SBS) for it mimics a large Bell state incorporating three small Bell states. Third, we show a protocol to create a three-atom electrons-nuclei entangled state which contains the three-body W and Green-berger–Horne–Zeilinger (GHZ) states simultaneously. These protocols possess high intrinsic fidelities, do not require single-site Rydberg addressing, and can be executed with large Rydberg Rabi frequencies in a weak, Gauss-scale magnetic field. The latter two protocols can enable measurement-based preparation of Bell, hyperentangled, and GHZ states, and, specifically, SBS can enable quantum dense coding where one can share three classical bits of information by sending one particle.
Implementation of accurate quantum gates based on Rydberg interactions is required for scalable quantum computing with ultracold neutral atoms, but has been held back by the difficulty of realizing high-fidelity two-qubit Rydberg gates. This study proposes an easily realizable controlled-ZZZ gate of high intrinsic fidelity, based on spin echo in Rydberg atoms. The ability to attain an accurate entangling Rydberg gate, with neither pulse shaping nor atomic vibrational-ground-state cooling, makes ultracold atoms promising for large-scale quantum computing.
Reaching fast and robust two-qubit gates with low infidelities has been an outstanding challenge for the long-term goal of useful quantum computers. Typically, optimizing the pulse shapes can minimize the gate infidelity and improve its robustness to certain types of errors; yet it remains incapable of speeding up the gate execution time which is fundamentally restricted by the attainable Rabi frequency in a realistic setup. In this work, we develop a fast implementation of two-qubit CZ gates using optimized ancillary drive to enhance the two-photon Rabi frequency between the ground and Rydberg states.This ancillary drive can work in an error-robustness framework without increasing the original gate infidelity in the absence of the drive. Considering the experimentally feasible parameters for 87^{87}87Rb atoms, we demonstrate that the execution time required for such CZ gates can be shortened by more than 30%\%% as compared to standard two-photon protocols arising the gate fidelity above 0.9954 by taking account of all relevant error sources. Our results reduce the high-power laser requirement and unlock the potential toward fast, high-fidelity quantum operations for large-scale quantum computation with neutral atoms.
We revisit the implementation of a two-qubit entangling gate, the M\o{}lmer-S\o{}rensen gate, using the adiabatic Rydberg dressing paradigm for neutral atoms as studied in [A. Mitra et al., Phys. Rev. A 101, 030301(R) (2020)]. We study the implementation of rapid adiabatic passage using a two-photon transition, which does not require the use of an ultraviolet laser, and can be implemented using only amplitude modulation of one field with all laser frequencies fixed. We find that entangling gate fidelities, comparable to the one-photon excitation, are achievable with the two-photon excitation. Moreover, we address how the adiabatic dressing protocol can be used to implement entangling gates outside the regime of a perfect Rydberg blockade. We show that, by using adiabatic dressing, we can achieve scaling of the gate fidelity set by the fundamental limits to entanglement generated by the Rydberg interactions while simultaneously retaining a limited population in the doubly excited Rydberg state. This allows for fast high-fidelity gates for atoms separated beyond the blockade radius.
Neutral atoms in optical tweezer arrays have emerged as a leading platform for quantum information processing. The fidelity of entangling gates mediated by Rydberg interactions has improved rapidly and is increasingly constrained by blackbody-radiation-induced transitions, which shorten Rydberg lifetimes and create contaminant states that can cause correlated errors. Cryogenic environments can suppress these transition rates by more than an order of magnitude. However, realizing a universal gate set in such an environment has remained an outstanding challenge. Here, we demonstrate a universal quantum gate set in a cryogenic 133^{133}133Cs atom array, with a single-qubit gate fidelity of 99.970(2)% and a raw two-qubit entangling-gate fidelity of 99.76(8)%, within the range of leading room-temperature implementations. The entangling gate uses direct single-photon coupling between the electronic ground state and a Rydberg PPP state, avoiding scattering and light shifts associated with two-photon coupling. The gate operates at a modest Rabi frequency of 2π×4.32π\times4.32π×4.3 MHz. The measured fidelity agrees with our error model dominated by atomic motion, indicating a straightforward route to higher fidelity through improved cooling, while the fundamental error contribution from Rydberg decay is below 3×10−43\times10^{-4}3×10−4. These results establish a path to entangling-gate fidelities substantially beyond the current state of the art through cryogenic suppression of Rydberg decay, reducing the overhead for fault-tolerant computation.
Rydberg-based two-qubit gate fidelities in neutral atom arrays are limited chiefly by laser intensity inhomogeneity and by detuning errors from frequency miscalibration, background-field drift, intermediate state light shift and Doppler shifts. Quantum optimal control can suppress the former, but no pulse can render a controlled-Z gate first-order insensitive to detuning. Here we show that this obstruction can be circumvented by designing Rydberg gate pulses with every leading-order detuning error relegated to single-qubit Z-rotations, which an echoed sequence removes. The resulting maximally-entangling ZZ gate has no leading-order response to arbitrary detunings on either atom, maintaining an infidelity below 10−310^{-3}10−3 within a much wider range of single-atom detunings than the time-optimal gates. We further show that a large fraction of residual error is dominated by population outside the computational subspace, which can be converted into heralded erasures. Our results significantly reduce the requirements on laser frequency stability and intensity homogeneity, field calibration and atomic temperature toward practical fault-tolerant quantum computing with neutral atoms.