Removing leakage-induced correlated errors in superconducting quantum error correction

McEwen, Matt; Kafri, Dvir; Chen, Z.; Atalaya, Juan; Satzinger, Kevin J.; Quintana, Chris; Klimov, Paul V.; Sank, D.; Gidney, Craig; Fowler, Austin G.; Arute, Frank; Arya, Kunal; Buckley, Bob B.; Burkett, Brian; Bushnell, Nicholas; Chiaro, B.; Collins, Roberto; Demura, Sean; Dunsworth, A.; Erickson, Catherine; Foxen, Brooks; Giustina, Marissa; Huang, Trent; Hong, Sabrina; Jeffrey, E.; Kim, S.; Kechedzhi, Kostyantyn; Kostritsa, Fedor; Laptev, Pavel; Megrant, A.; Mi, Xiao; Mutus, J.; Naaman, Ofer; Neeley, M.; Neill, C.; Niu, Murphy Yuezhen; Paler, Alexandru; Redd, Nicholas; Roushan, P.; White, Theodore C.; Yao, Jianan; Yeh, P.; Zalcman, Adam; Chen, Yu; Smelyanskiy, Vadim; Martinis, John M.; Neven, Hartmut; Kelly, J.; Korotkov, Alexander N.; Petukhov, A.; Barends, R.

doi:10.1038/s41467-021-21982-y

Cited by 81 publications

(48 citation statements)

References 38 publications

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“…Aside from these boundary effects, we observe that the average detection event fraction is 11% and is stable across all 50 rounds of the experiment, a key finding for the feasibility of QEC. Previous experiments had observed detections rising with number of rounds 21 , and we attribute our experiment's stability to the use of reset to remove leakage in every round 35 .…”

Section: Exponential Suppression Of Bit or Phase Errors With Cyclic Error Correctionsupporting

confidence: 51%

“…First, we use the reset protocol introduced in ref. 35 , which removes population from excited states (including non-computational states) by sweeping the frequency of each measure qubit through that of its readout resonator. This reset operation is appended after each measurement in the QEC circuit and produces the ground state with error below 0.5% 35 in 280 ns.…”

Section: Qec With the Sycamore Processormentioning

confidence: 99%

“… 35 , which removes population from excited states (including non-computational states) by sweeping the frequency of each measure qubit through that of its readout resonator. This reset operation is appended after each measurement in the QEC circuit and produces the ground state with error below 0.5% 35 in 280 ns. Second, we implement a 26-ns controlled- Z (CZ) gate using a direct swap between the joint states and of the two qubits (refs.…”

Section: Qec With the Sycamore Processormentioning

confidence: 99%

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Exponential suppression of bit or phase errors with cyclic error correction

Chen¹,

Satzinger²,

Atalaya³

et al. 2021

Nature

Self Cite

267

125

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Realizing the potential of quantum computing requires sufficiently low logical error rates1. Many applications call for error rates as low as 10−15 (refs. 2–9), but state-of-the-art quantum platforms typically have physical error rates near 10−3 (refs. 10–14). Quantum error correction15–17 promises to bridge this divide by distributing quantum logical information across many physical qubits in such a way that errors can be detected and corrected. Errors on the encoded logical qubit state can be exponentially suppressed as the number of physical qubits grows, provided that the physical error rates are below a certain threshold and stable over the course of a computation. Here we implement one-dimensional repetition codes embedded in a two-dimensional grid of superconducting qubits that demonstrate exponential suppression of bit-flip or phase-flip errors, reducing logical error per round more than 100-fold when increasing the number of qubits from 5 to 21. Crucially, this error suppression is stable over 50 rounds of error correction. We also introduce a method for analysing error correlations with high precision, allowing us to characterize error locality while performing quantum error correction. Finally, we perform error detection with a small logical qubit using the 2D surface code on the same device18,19 and show that the results from both one- and two-dimensional codes agree with numerical simulations that use a simple depolarizing error model. These experimental demonstrations provide a foundation for building a scalable fault-tolerant quantum computer with superconducting qubits.

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Section: Exponential Suppression Of Bit or Phase Errors With Cyclic Error Correctionsupporting

confidence: 51%

Section: Qec With the Sycamore Processormentioning

confidence: 99%

Section: Qec With the Sycamore Processormentioning

confidence: 99%

See 1 more Smart Citation

Exponential suppression of bit or phase errors with cyclic error correction

Chen¹,

Satzinger²,

Atalaya³

et al. 2021

Nature

Self Cite

267

125

View full text Add to dashboard Cite

show abstract

“…Then it has been clarified that nonlinear errors give serious degradations of the capability of quantum computer, by the recurrence effect due to quantum correlation and also by collective decoherence . In order to cope with the quantum errors described in this paper, or to avoid this situation, one method is to further develop the conventional quantum error correction theory based on quantum noise analysis, or to establish a new way to physically suppress such errors [ 32 , 33 , 34 ]. Recently, a number of previously unknown and extremely difficult challenges in the development of an error correctable quantum computer have been reported [ 35 , 36 , 37 , 38 ].…”

Section: Discussionmentioning

confidence: 99%

Introduction to Semi-Classical Analysis for Digital Errors of Qubit in Quantum Processor

Hirota

2021

Entropy

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In recent years, remarkable progress has been achieved in the development of quantum computers. For further development, it is important to clarify properties of errors by quantum noise and environment noise. However, when the system scale of quantum processors is expanded, it has been pointed out that a new type of quantum error, such as nonlinear error, appears. It is not clear how to handle such new effects in information theory. First of all, one should make the characteristics of the error probability of qubits clear as communication channel error models in information theory. The purpose of this paper is to survey the progress for modeling the quantum noise effects that information theorists are likely to face in the future, to cope with such nontrivial errors mentioned above. This paper explains a channel error model to represent strange properties of error probability due to new quantum noise. By this model, specific examples on the features of error probability caused by, for example, quantum recurrence effects, collective relaxation, and external force, are given. As a result, it is possible to understand the meaning of strange features of error probability that do not exist in classical information theory without going through complex physical phenomena.

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“…Further experiments could use photon‐assisted tunneling in an NIS junction to cool a device such as a qubit or a resonator. [ 27 ] Present practical methods used in more advanced quantum processors [ 110 ] for initialization also make use of tuning of dissipation, based on the observation that it is more convenient experimentally to tune the qubit rather than the bath. In a standard transmon qubit coupled to the readout coplanar waveguide cavity, the qubit (with a higher frequency than the cavity) is adiabatically tuned down towards resonance with the cavity, which swaps the excess population from the excited states of the qubit into the cavity.…”

Section: Experimental Methods For Control Of Dissipationmentioning

confidence: 99%

Engineering Dissipation with Resistive Elements in Circuit Quantum Electrodynamics

Cattaneo

Paraoanu

2021

Adv Quantum Tech

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The importance of dissipation engineering ranges from universal quantum computation to non‐equilibrium quantum thermodynamics. In recent years, more and more theoretical and experimental studies have shown the relevance of this topic for circuit quantum electrodynamics, one of the major platforms in the race for a quantum computer. This article discusses how to simulate thermal baths by inserting resistive elements in networks of superconducting qubits. Apart from pedagogically reviewing the phenomenological and microscopic models of a resistor as thermal bath with Johnson–Nyquist noise, the paper introduces some new results in the weak coupling limit, showing that the most common examples of open quantum systems can be simulated through capacitively coupled superconducting qubits and resistors. The aim of the manuscript, written with a broad audience in mind, is to be both an instructive tutorial about how to derive and characterize the Hamiltonian of general dissipative superconducting circuits with capacitive coupling, and a review of the most relevant and topical theoretical and experimental works focused on resistive elements and dissipation engineering.

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Removing leakage-induced correlated errors in superconducting quantum error correction

Cited by 81 publications

References 38 publications

Exponential suppression of bit or phase errors with cyclic error correction

Exponential suppression of bit or phase errors with cyclic error correction

Introduction to Semi-Classical Analysis for Digital Errors of Qubit in Quantum Processor

Engineering Dissipation with Resistive Elements in Circuit Quantum Electrodynamics

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