Mid-circuit correction of correlated phase errors using an array of spectator qubits

Singh, Kevin; Bradley, C. E.; Anand, Shraddha; Ramesh, V.; White, R.; Bernien, Hannes

doi:10.1126/science.ade5337

Cited by 43 publications

(8 citation statements)

References 48 publications

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“… 8 ). Deep computation will further require continuous reloading of atoms from a reservoir source 11 , 15 . Continued scaling will benefit from improving encoding efficiency, for example, by using quantum low-density-parity-check codes 55 , 56 , using erasure conversion 13 , 33 , 57 or noise bias 35 and optimizing the choice of (possibly several) atomic species 11 , 14 , 47 , as well as advanced optical controls 34 .…”

Section: Discussionmentioning

confidence: 99%

Logical quantum processor based on reconfigurable atom arrays

Bluvstein,

Evered,

Geim

et al. 2023

Nature

193

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Suppressing errors is the central challenge for useful quantum computing1, requiring quantum error correction (QEC)2–6 for large-scale processing. However, the overhead in the realization of error-corrected ‘logical’ qubits, in which information is encoded across many physical qubits for redundancy2–4, poses substantial challenges to large-scale logical quantum computing. Here we report the realization of a programmable quantum processor based on encoded logical qubits operating with up to 280 physical qubits. Using logical-level control and a zoned architecture in reconfigurable neutral-atom arrays7, our system combines high two-qubit gate fidelities8, arbitrary connectivity7,9, as well as fully programmable single-qubit rotations and mid-circuit readout10–15. Operating this logical processor with various types of encoding, we demonstrate improvement of a two-qubit logic gate by scaling surface-code6 distance from d = 3 to d = 7, preparation of colour-code qubits with break-even fidelities5, fault-tolerant creation of logical Greenberger–Horne–Zeilinger (GHZ) states and feedforward entanglement teleportation, as well as operation of 40 colour-code qubits. Finally, using 3D [[8,3,2]] code blocks16,17, we realize computationally complex sampling circuits18 with up to 48 logical qubits entangled with hypercube connectivity19 with 228 logical two-qubit gates and 48 logical CCZ gates20. We find that this logical encoding substantially improves algorithmic performance with error detection, outperforming physical-qubit fidelities at both cross-entropy benchmarking and quantum simulations of fast scrambling21,22. These results herald the advent of early error-corrected quantum computation and chart a path towards large-scale logical processors.

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Section: Discussionmentioning

confidence: 99%

Logical quantum processor based on reconfigurable atom arrays

Bluvstein,

Evered,

Geim

et al. 2023

Nature

193

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“…The recent experiment reported in ref. 28 has many spectator qubits available; using those in a coordinated way may offer some of the advantages of the spectator mode regarding measurement imprecision. Furthermore, one could imagine that the advantages of parametric driving to the spectator mode could be realized in spin ensembles using spin squeezing.…”

Section: Discussionmentioning

confidence: 99%

“…To this end, there has been a flurry of activity developing spectator qubits (SQ) protocols which explicitly use spatial correlations to fight noise 24 – 28 . The SQ are a dedicated set of qubits in a quantum processor or register which do not interact with the data qubits – those whose states are to be protected – but are in close enough physical proximity to be susceptible to the same noise.…”

Section: Introductionmentioning

confidence: 99%

Surpassing spectator qubits with photonic modes and continuous measurement for Heisenberg-limited noise mitigation

Lingenfelter,

Clerk

2023

npj Quantum Inf

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Noise is an ever-present challenge to the creation and preservation of fragile quantum states. Recent work suggests that spatial noise correlations can be harnessed as a resource for noise mitigation via the use of spectator qubits to measure environmental noise. In this work we generalize this concept from spectator qubits to a spectator mode: a photonic mode which continuously measures spatially correlated classical dephasing noise and applies a continuous correction drive to frequency-tunable data qubits. Our analysis shows that by using many photon states, spectator modes can surpass many of the quantum measurement constraints that limit spectator qubit approaches. We also find that long-time data qubit dephasing can be arbitrarily suppressed, even for white noise dephasing. Further, using a squeezing (parametric) drive, the error in the spectator mode approach can exhibit Heisenberg-limited scaling in the number of photons used. We also show that spectator mode noise mitigation can be implemented completely autonomously using engineered dissipation. In this case no explicit measurement or processing of a classical measurement record is needed. Our work establishes spectator modes as a potentially powerful alternative to spectator qubits for noise mitigation.

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“…Next to being faster and non-destructive, the latter technique has the advantage that much fewer photons must be scattered for detection, reducing atom heating and cross-talk problems at the expense of serial readout. Parallel mid-circuit measurements of qubits have also been demonstrated recently [8,[80][81][82][83][84].…”

Section: Measurementsmentioning

confidence: 95%

“…Regarding quantum error correction, most schemes require mid-circuit measurements and real-time feedback, a procedure which has been demonstrated lately with NAs [8,83,84] but remains challenging. Therefore, progress on measurement-free fault-tolerant quantum error correction might be promising for NAs [95][96][97].…”

Section: Fault-tolerant Qc and Error Correctionmentioning

confidence: 99%

Computational capabilities and compiler development for neutral atom quantum processors—connecting tool developers and hardware experts

Schmid,

Locher,

Rispler

et al. 2024

Quantum Sci. Technol.

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Neutral Atom Quantum Computing (NAQC) emerges as a promising hardware platform primarily due to its long coherence times and scalability. Additionally, NAQC offers computational advantages encompassing potential long-range connectivity, native multi-qubit gate support, and the ability to physically rearrange qubits with high fidelity. However, for the successful operation of a NAQC processor, one additionally requires new software tools to translate high-level algorithmic descriptions into a hardware executable representation, taking maximal advantage of the hardware capabilities. Realizing new software tools requires a close connection between tool developers and hardware experts to ensure that the corresponding software tools obey the corresponding physical constraints. This work aims to provide a basis to establish this connection by investigating the broad spectrum of capabilities intrinsic to the NAQC platform and its implications on the compilation process. To this end, we first review the physical background of NAQC and derive how it affects the overall compilation process by formulating suitable constraints and figures of merit. We then provide a summary of the compilation process and discuss currently available software tools in this overview. Finally, we present selected case studies and employ the discussed figures of merit to evaluate the different capabilities of NAQC and compare them between two hardware setups.

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Mid-circuit correction of correlated phase errors using an array of spectator qubits

Cited by 43 publications

References 48 publications

Logical quantum processor based on reconfigurable atom arrays

Logical quantum processor based on reconfigurable atom arrays

Surpassing spectator qubits with photonic modes and continuous measurement for Heisenberg-limited noise mitigation

Computational capabilities and compiler development for neutral atom quantum processors—connecting tool developers and hardware experts

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