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:2603.13492

Qubit syndrome measurements with a high fidelity Rb-Cs Rydberg gate

J. Miles, M. T. Lichtman, A. M. Scott, J. Scott, S. A. Norrell, M. J. Bedalov, D. A. Belknap, D. C. Cole, S. Y. Eubanks, M. Gillette, P. Gokhale, J. Goldwin, M. Iliev, R. A. Jones, K. W. Kuper, D. Mason, P. T. Mitchell, J. D. Murphree, N. A. Neff-Mallon, T. W. Noel, A. G. Radnaev, I. V. Vinogradov, M. Saffman

quant-phSubmitted Mar 13, 2026• Announced Mar 17, 2026• 0 citations• Revised Jul 30, 2026 (v4)
v1 · Mar 13, 2026v2 · Mar 19, 2026v3 · Mar 26, 2026v4 · Jul 30, 2026
arXivHTMLPDF

Abstract

We demonstrate an inter-species entangling Rydberg gate between rubidium (Rb) and cesium (Cs) atoms with fidelity $\mathcal F = 0.975\pm 0.002$. The two-species atom array enables in-place quantum non-demolition (QND) qubit measurements which are a key capability for quantum error correction. We demonstrate this functionality with multi-atom error syndrome measurements achieving QND measurement fidelities of ${\mathcal F}_{\rm QND} = 0.933(12)$ and $0.865(17)$ for two- and three-qubit plaquettes, respectively.

Comments
updated descriptions

Related papers

Qubit Syndrome Measurements with a High-Fidelity Rb-Cs Rydberg Gate

Jared A. Miles, Martin Lichtman, A. M. Scott +20 more

We demonstrate an interspecies entangling Rydberg gate between rubidium (Rb) and cesium (Cs) atoms with fidelity F=0.975±0.002. The two-species atom array enables in-place quantum nondemolition (QND) qubit measurements which are a key capability for quantum error correction. We demonstrate this functionality with multiatom error syndrome measurements achieving QND measurement fidelities of F_{QND}=0.933(12) and 0.865(17) for two- and three-qubit plaquettes, respectively.

Physical Review Letters•Aug 3, 2026•2 citations

A dual-species Rydberg array

Shraddha Anand, C. E. Bradley, Ryan White +3 more

Large-scale Rydberg atom arrays are used for highly coherent analogue quantum simulations and for digital quantum computations. However, advanced quantum protocols, such as quantum error correction, require midcircuit qubit operations, including the replenishment, reset and read-out of a subset of qubits. A compelling strategy for unlocking these capabilities is a dual-species architecture in which a second atomic species is controlled independently and entangled with the first through Rydberg interactions. Here, we realize a dual-species Rydberg array consisting of rubidium and caesium atoms and explore regimes of interactions and dynamics not accessible in single-species architectures. We achieve enhanced interspecies interactions by electrically tuning the Rydberg states close to a Förster resonance. In this regime, we demonstrate an interspecies Rydberg blockade and implement a quantum state transfer from one species to another. We then generate a Bell state between Rb and Cs hyperfine qubits through an interspecies controlled-phase gate. Finally, we combine interspecies entanglement with a native midcircuit read-out to achieve quantum non-demolition measurements. Rydberg atoms in optical tweezers are a promising platform for quantum information science. A platform composed of dual-species Rydberg arrays has been realized, offering access to unexplored interaction regimes and crosstalk-free midcircuit control.

arXiv:2401.10325•Nature Physics•Sep 20, 2024•87 citations

Multi-Qubit Stabilizer Readout on a Dual-Species Rydberg Array

Yu Wang, Ryan Cimmino, Kenneth Wang +7 more

The ability to locally control and measure subsets of ancilla qubits in an efficient and crosstalk-free manner is a key ingredient in quantum error correction (QEC). Dual-species neutral atom arrays offer an ideal implementation of these capabilities, enabling independent state preparation, manipulation, and detection on each species. In this work, we realize such a dual-species Rydberg array of Na and Cs atoms trapped in co-localized 2D optical tweezer arrays, using Na as an ancilla to measure stabilizers of surrounding Cs data qubits. We identify the finite interspecies Rydberg-Rydberg interaction strength as a practical obstacle to high-fidelity multi-body entanglement and show that, by tuning the Rabi frequency and the detuning of the Rydberg driving field, the resulting geometric phase error can be compensated. This yields a protocol for simultaneous, non-destructive, in situ stabilizer readout of multiple data qubits via global pulses alone. Using this protocol, we demonstrate non-destructive measurement of Pauli-Z stabilizers on four-qubit Cs plaquettes via a single global Rydberg pulse sequence. Our results demonstrate dual-species tweezer arrays as a promising route towards scalable QEC and open the door to new quantum control protocols leveraging both interspecies and intraspecies interactions.

quant-pharXiv:2605.10924•May 12, 2026•0 citations

High-Fidelity Inter-Species Rydberg Gates with Two-Photon Driving

Shuan Wang, Kevin Singh

Recently, neutral atom arrays have become known for their promising potential in quantum information processing. High-fidelity entangling operations are typically achieved by exciting atoms to high-lying Rydberg states through two-photon processes. To improve the performance of these systems at the hardware level, dual-species strategies have been applied to enhance readout, error correction, and reloading in neutral atom systems. However, the influence of laser crosstalk arising from two-photon excitation for dual-species systems has remained largely unexplored in the literature. Here, we develop a model that incorporates the influence of crosstalk in inter-species Rydberg gates with two-photon driving. We demonstrate that the influence of this crosstalk can be suppressed to arbitrarily small levels through appropriate gate design, with gate fidelities greater than $99.8\%$ achievable with conservative experimental parameters in the near-detuned case of an $^{85}$Rb/$^{87}$Rb system. We also outline how this fidelity can be further enhanced through improvements to the Rydberg excitation.

quant-pharXiv:2610.08926•Oct 8, 2026•0 citations

Fast measurements and multiqubit gates in dual-species atomic arrays

David Petrosyan, Sam A. Norrell, C. Poole +1 more

We propose and analyze an approach for fast syndrome measurements in an array of rubidium and cesium atomic qubits. The scheme works by implementing an interspecies controlled-not (cnot${}_{k}$) gate, entangling one cesium ancilla qubit with $k\ensuremath{\ge}1$ rubidium qubits which are then used for state measurement. Utilizing Rydberg states with different interspecies and intraspecies interaction strengths, the proposal provides a syndrome measurement fidelity of $\mathcal{F}>0.9999$ in less than $5\phantom{\rule{0.28em}{0ex}}\textmu{}\mathrm{s}$ of integration time.

arXiv:2406.07356•Physical Review A•Oct 8, 2024•13 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
We demonstrate an inter-species entangling Rydberg gate between rubidium (Rb) and cesium (Cs) atoms with fidelity F=0.975±0.002\mathcal F = 0.975\pm 0.002F=0.975±0.002. The two-species atom array enables in-place quantum non-demolition (QND) qubit measurements which are a key capability for quantum error correction. We demonstrate this functionality with multi-atom error syndrome measurements achieving QND measurement fidelities of FQND=0.933(12){\mathcal F}_{\rm QND} = 0.933(12)FQND​=0.933(12) and 0.865(17)0.865(17)0.865(17) for two- and three-qubit plaquettes, respectively.
Large-scale Rydberg atom arrays are used for highly coherent analogue quantum simulations and for digital quantum computations. However, advanced quantum protocols, such as quantum error correction, require midcircuit qubit operations, including the replenishment, reset and read-out of a subset of qubits. A compelling strategy for unlocking these capabilities is a dual-species architecture in which a second atomic species is controlled independently and entangled with the first through Rydberg interactions. Here, we realize a dual-species Rydberg array consisting of rubidium and caesium atoms and explore regimes of interactions and dynamics not accessible in single-species architectures. We achieve enhanced interspecies interactions by electrically tuning the Rydberg states close to a Förster resonance. In this regime, we demonstrate an interspecies Rydberg blockade and implement a quantum state transfer from one species to another. We then generate a Bell state between Rb and Cs hyperfine qubits through an interspecies controlled-phase gate. Finally, we combine interspecies entanglement with a native midcircuit read-out to achieve quantum non-demolition measurements. Rydberg atoms in optical tweezers are a promising platform for quantum information science. A platform composed of dual-species Rydberg arrays has been realized, offering access to unexplored interaction regimes and crosstalk-free midcircuit control.
The ability to locally control and measure subsets of ancilla qubits in an efficient and crosstalk-free manner is a key ingredient in quantum error correction (QEC). Dual-species neutral atom arrays offer an ideal implementation of these capabilities, enabling independent state preparation, manipulation, and detection on each species. In this work, we realize such a dual-species Rydberg array of Na and Cs atoms trapped in co-localized 2D optical tweezer arrays, using Na as an ancilla to measure stabilizers of surrounding Cs data qubits. We identify the finite interspecies Rydberg-Rydberg interaction strength as a practical obstacle to high-fidelity multi-body entanglement and show that, by tuning the Rabi frequency and the detuning of the Rydberg driving field, the resulting geometric phase error can be compensated. This yields a protocol for simultaneous, non-destructive, in situ stabilizer readout of multiple data qubits via global pulses alone. Using this protocol, we demonstrate non-destructive measurement of Pauli-Z stabilizers on four-qubit Cs plaquettes via a single global Rydberg pulse sequence. Our results demonstrate dual-species tweezer arrays as a promising route towards scalable QEC and open the door to new quantum control protocols leveraging both interspecies and intraspecies interactions.
Recently, neutral atom arrays have become known for their promising potential in quantum information processing. High-fidelity entangling operations are typically achieved by exciting atoms to high-lying Rydberg states through two-photon processes. To improve the performance of these systems at the hardware level, dual-species strategies have been applied to enhance readout, error correction, and reloading in neutral atom systems. However, the influence of laser crosstalk arising from two-photon excitation for dual-species systems has remained largely unexplored in the literature. Here, we develop a model that incorporates the influence of crosstalk in inter-species Rydberg gates with two-photon driving. We demonstrate that the influence of this crosstalk can be suppressed to arbitrarily small levels through appropriate gate design, with gate fidelities greater than 99.8%99.8\%99.8% achievable with conservative experimental parameters in the near-detuned case of an 85^{85}85Rb/87^{87}87Rb system. We also outline how this fidelity can be further enhanced through improvements to the Rydberg excitation.
We propose and analyze an approach for fast syndrome measurements in an array of rubidium and cesium atomic qubits. The scheme works by implementing an interspecies controlled-not (cnotk{}_{k}k​) gate, entangling one cesium ancilla qubit with $k\ensuremath{\ge}1$ rubidium qubits which are then used for state measurement. Utilizing Rydberg states with different interspecies and intraspecies interaction strengths, the proposal provides a syndrome measurement fidelity of F>0.9999\mathcal{F}>0.9999F>0.9999 in less than $5\phantom{\rule{0.28em}{0ex}}\textmu{}\mathrm{s}$ of integration time.
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.