Pub Date : 2025-12-14DOI: 10.1038/s41534-025-01153-3
Zhiyuan Wang, Qing He, Zijing Zhang
Quantum process tomography (QPT) is a crucial technique for characterizing unknown quantum channels. However, traditional QPT methods encounter scalability problems as the particle numbers increase, requiring exponentially more state preparations and measurement operators. The characteristics of sparse target channels (e.g., multiqubit phase-shift gates) can be obtained by measuring only a few specific matrix elements without requiring global QPT. Therefore, direct quantum channel characterization is vital. This paper proposes a direct protocol for both qubit and qudit systems that extracts specific process matrix elements without full reconstruction. The measurement operator requirements remain independent of system size and dimensionality. Notably, the proposed protocol uses nondestructive measurements and preserves qubits after evolution through unknown processes for potential reuse, making it uniquely promising for applications such as real-time monitoring of noise processes in quantum error correction and real-time feedback control requiring quantum state preservation. To validate the theoretical correctness of our approach, we conducted experimental demonstrations of both the unitary and non-unitary processes of single qubits using a nuclear magnetic resonance system on the SpinQ quantum cloud platform. The experimental results confirmed the correctness and effectiveness of the proposed method.
{"title":"Efficient non-destructive direct characterization of arbitrary many-body quantum channels","authors":"Zhiyuan Wang, Qing He, Zijing Zhang","doi":"10.1038/s41534-025-01153-3","DOIUrl":"https://doi.org/10.1038/s41534-025-01153-3","url":null,"abstract":"Quantum process tomography (QPT) is a crucial technique for characterizing unknown quantum channels. However, traditional QPT methods encounter scalability problems as the particle numbers increase, requiring exponentially more state preparations and measurement operators. The characteristics of sparse target channels (e.g., multiqubit phase-shift gates) can be obtained by measuring only a few specific matrix elements without requiring global QPT. Therefore, direct quantum channel characterization is vital. This paper proposes a direct protocol for both qubit and qudit systems that extracts specific process matrix elements without full reconstruction. The measurement operator requirements remain independent of system size and dimensionality. Notably, the proposed protocol uses nondestructive measurements and preserves qubits after evolution through unknown processes for potential reuse, making it uniquely promising for applications such as real-time monitoring of noise processes in quantum error correction and real-time feedback control requiring quantum state preservation. To validate the theoretical correctness of our approach, we conducted experimental demonstrations of both the unitary and non-unitary processes of single qubits using a nuclear magnetic resonance system on the SpinQ quantum cloud platform. The experimental results confirmed the correctness and effectiveness of the proposed method.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"9 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145746785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1038/s41534-025-01142-6
Boyuan Wang, Zhaoyuan Meng, Yaomin Zhao, Yue Yang
Quantum computing holds transformative potential for simulating nonlinear physical systems, such as fluid turbulence. However, mapping nonlinear dynamics to the linear operations required by quantum hardware remains a fundamental challenge. Here, we bridge this gap by introducing a novel node-level ensemble description of a lattice gas, which enables the simulation of nonlinear fluid dynamics on quantum computers. This approach combines the advantages of the lattice Boltzmann method with low-dimensional representation (computational cost) and lattice gas cellular automata with linear collision treatment (quantum compatibility). Building on this framework, we propose a quantum lattice Boltzmann method that relies on linear operations with medium dimensionality, offering the potential for quantum speedup. We validated the algorithm through simulations of vortex-pair merging and decaying turbulence on up to 16.8 million computational grid points. The results demonstrate remarkable agreement with direct numerical simulation, effectively capturing the essential nonlinear mechanisms of fluid dynamics. This work potentially advances the development of quantum algorithms for other nonlinear problems across various transport phenomena in engineering.
{"title":"Quantum lattice Boltzmann method for simulating nonlinear fluid dynamics","authors":"Boyuan Wang, Zhaoyuan Meng, Yaomin Zhao, Yue Yang","doi":"10.1038/s41534-025-01142-6","DOIUrl":"https://doi.org/10.1038/s41534-025-01142-6","url":null,"abstract":"Quantum computing holds transformative potential for simulating nonlinear physical systems, such as fluid turbulence. However, mapping nonlinear dynamics to the linear operations required by quantum hardware remains a fundamental challenge. Here, we bridge this gap by introducing a novel node-level ensemble description of a lattice gas, which enables the simulation of nonlinear fluid dynamics on quantum computers. This approach combines the advantages of the lattice Boltzmann method with low-dimensional representation (computational cost) and lattice gas cellular automata with linear collision treatment (quantum compatibility). Building on this framework, we propose a quantum lattice Boltzmann method that relies on linear operations with medium dimensionality, offering the potential for quantum speedup. We validated the algorithm through simulations of vortex-pair merging and decaying turbulence on up to 16.8 million computational grid points. The results demonstrate remarkable agreement with direct numerical simulation, effectively capturing the essential nonlinear mechanisms of fluid dynamics. This work potentially advances the development of quantum algorithms for other nonlinear problems across various transport phenomena in engineering.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"15 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145746830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1038/s41534-025-01154-2
Gabriele Agliardi, Giorgio Cortiana, Anton Dekusar, Kumar Ghosh, Naeimeh Mohseni, Corey O’Meara, Víctor Valls, Kavitha Yogaraj, Sergiy Zhuk
Fidelity quantum kernels provide a provable advantage on classification problems where a group structure in the data can be exploited. However, in practical applications, the group structure may be unknown or approximate, and scaling to the ‘utility’ regime is affected by exponential concentration. We prove that an ideal behavior of fidelity kernels is always associated with a (possibly unknown) group structure in the feature map. We also propose a mitigation strategy for fidelity kernels, called Bit Flip Tolerance (BFT), to alleviate exponential concentration. Applied to real-world data with unknown structure, related to the charge schedule of electric vehicles, BFT proves useful on 40 + qubits, where mitigated accuracies reach 80%, in line with classical, compared to 33% without BFT. Through a synthetic dataset with 156 qubits, we obtain an accuracy of 80%, compared to 83% of classical models, and 37% of unmitigated quantum. This constitutes the largest experiment of quantum machine learning on IBM devices to date.
{"title":"Mitigating exponential concentration in covariant quantum kernels for subspace and real-world data","authors":"Gabriele Agliardi, Giorgio Cortiana, Anton Dekusar, Kumar Ghosh, Naeimeh Mohseni, Corey O’Meara, Víctor Valls, Kavitha Yogaraj, Sergiy Zhuk","doi":"10.1038/s41534-025-01154-2","DOIUrl":"https://doi.org/10.1038/s41534-025-01154-2","url":null,"abstract":"Fidelity quantum kernels provide a provable advantage on classification problems where a group structure in the data can be exploited. However, in practical applications, the group structure may be unknown or approximate, and scaling to the ‘utility’ regime is affected by exponential concentration. We prove that an ideal behavior of fidelity kernels is always associated with a (possibly unknown) group structure in the feature map. We also propose a mitigation strategy for fidelity kernels, called Bit Flip Tolerance (BFT), to alleviate exponential concentration. Applied to real-world data with unknown structure, related to the charge schedule of electric vehicles, BFT proves useful on 40 + qubits, where mitigated accuracies reach 80%, in line with classical, compared to 33% without BFT. Through a synthetic dataset with 156 qubits, we obtain an accuracy of 80%, compared to 83% of classical models, and 37% of unmitigated quantum. This constitutes the largest experiment of quantum machine learning on IBM devices to date.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"20 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145746787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1038/s41534-025-01140-8
Lorenzo Peri, Alberto Gomez-Saiz, Christopher J. B. Ford, M. Fernando Gonzalez-Zalba
Scalable solid-state quantum computers will require integration with analog and digital electronics. Efficiently simulating the quantum-classical electronic interface is hence of paramount importance. Here, we present Verilog-A compact models with a focus on quantum-dot-based systems, relevant to semiconductor- and Majorana-based quantum computing. Our models are capable of faithfully reproducing coherent quantum behavior and decoherence effects within a standard electronic circuit simulator, enabling compromise-free co-simulation of hybrid quantum devices. In particular, we present results from co-simulations performed in Cadence Spectre®, showcasing coherent quantum phenomena in circuits with both quantum and classical components using an industry-standard electronic design and automation tool. Our work paves the way for a new paradigm in the design of quantum systems, which leverages the many decades of development of electronic computer-aided design and automation tools in the semiconductor industry to now simulate and optimize quantum processing units, quantum-classical interfaces, and hybrid quantum-analog circuits.
{"title":"Compact quantum dot models for analog microwave co-simulation","authors":"Lorenzo Peri, Alberto Gomez-Saiz, Christopher J. B. Ford, M. Fernando Gonzalez-Zalba","doi":"10.1038/s41534-025-01140-8","DOIUrl":"https://doi.org/10.1038/s41534-025-01140-8","url":null,"abstract":"Scalable solid-state quantum computers will require integration with analog and digital electronics. Efficiently simulating the quantum-classical electronic interface is hence of paramount importance. Here, we present Verilog-A compact models with a focus on quantum-dot-based systems, relevant to semiconductor- and Majorana-based quantum computing. Our models are capable of faithfully reproducing coherent quantum behavior and decoherence effects within a standard electronic circuit simulator, enabling compromise-free co-simulation of hybrid quantum devices. In particular, we present results from co-simulations performed in Cadence Spectre®, showcasing coherent quantum phenomena in circuits with both quantum and classical components using an industry-standard electronic design and automation tool. Our work paves the way for a new paradigm in the design of quantum systems, which leverages the many decades of development of electronic computer-aided design and automation tools in the semiconductor industry to now simulate and optimize quantum processing units, quantum-classical interfaces, and hybrid quantum-analog circuits.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"7 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145746788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-12DOI: 10.1038/s41534-025-01155-1
Mengxin Du, Chao Zhang, Yiu Tung Poon, Bei Zeng
Quantum error correction (QEC) is essential for protecting quantum information against noise, yet understanding the structure of the Knill-Laflamme (KL) coefficients (left{{lambda }_{ij}right}) from the condition (P{E}_{i}^{dagger }{E}_{j}P={lambda }_{ij}P) remains challenging, particularly for nonadditive codes. In this work, we introduce the signature vector (overrightarrow{lambda }(P)), composed of the off-diagonal KL coefficients (left{{lambda }_{ij}right}), where each coefficient corresponds to equivalence classes of errors counted only once. We define its Euclidean norm λ*(P) as a scalar measure representing the total strength of error correlations within the code subspace defined by the projector P. We parameterize P on a Stiefel manifold and formulate an optimization problem based on the KL conditions to systematically explore possible values of λ*. Moreover, we show that, for ((n, K, d)) codes, λ* is invariant under local unitary transformations. Applying our approach to the ((6, 2, 3)) quantum code, we find that ({lambda }_{min }^{* }=sqrt{0.6}) and ({lambda }_{max }^{* }=1), with λ* = 1 corresponding to a known degenerate stabilizer code. We construct continuous families of new nonadditive codes parameterized by vectors in ({{mathbb{R}}}^{5}), with λ* varying over the interval ([sqrt{0.6},1]). For the ((7, 2, 3)) code, we identify ({lambda }_{min }^{* }=0) (corresponding to the non-degenerate Steane code) and ({lambda }_{max }^{* }=sqrt{7}) (corresponding to the permutation-invariant code by Pollatsek and Ruskai), and we demonstrate continuous paths connecting these extremes via cyclic codes characterized solely by λ*. Our findings provide new insights into the structure of quantum codes, advance the theoretical foundations of QEC, and open new avenues for investigating intricate relationships between code subspaces and error correlations.
{"title":"Characterizing quantum codes via the coefficients in Knill-Laflamme conditions","authors":"Mengxin Du, Chao Zhang, Yiu Tung Poon, Bei Zeng","doi":"10.1038/s41534-025-01155-1","DOIUrl":"https://doi.org/10.1038/s41534-025-01155-1","url":null,"abstract":"Quantum error correction (QEC) is essential for protecting quantum information against noise, yet understanding the structure of the Knill-Laflamme (KL) coefficients (left{{lambda }_{ij}right}) from the condition (P{E}_{i}^{dagger }{E}_{j}P={lambda }_{ij}P) remains challenging, particularly for nonadditive codes. In this work, we introduce the signature vector (overrightarrow{lambda }(P)), composed of the off-diagonal KL coefficients (left{{lambda }_{ij}right}), where each coefficient corresponds to equivalence classes of errors counted only once. We define its Euclidean norm λ*(P) as a scalar measure representing the total strength of error correlations within the code subspace defined by the projector P. We parameterize P on a Stiefel manifold and formulate an optimization problem based on the KL conditions to systematically explore possible values of λ*. Moreover, we show that, for ((n, K, d)) codes, λ* is invariant under local unitary transformations. Applying our approach to the ((6, 2, 3)) quantum code, we find that ({lambda }_{min }^{* }=sqrt{0.6}) and ({lambda }_{max }^{* }=1), with λ* = 1 corresponding to a known degenerate stabilizer code. We construct continuous families of new nonadditive codes parameterized by vectors in ({{mathbb{R}}}^{5}), with λ* varying over the interval ([sqrt{0.6},1]). For the ((7, 2, 3)) code, we identify ({lambda }_{min }^{* }=0) (corresponding to the non-degenerate Steane code) and ({lambda }_{max }^{* }=sqrt{7}) (corresponding to the permutation-invariant code by Pollatsek and Ruskai), and we demonstrate continuous paths connecting these extremes via cyclic codes characterized solely by λ*. Our findings provide new insights into the structure of quantum codes, advance the theoretical foundations of QEC, and open new avenues for investigating intricate relationships between code subspaces and error correlations.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"112 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145746789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-09DOI: 10.1038/s41534-025-01150-6
Juan S. Rojas-Arias, Yohei Kojima, Kenta Takeda, Peter Stano, Takashi Nakajima, Jun Yoneda, Akito Noiri, Takashi Kobayashi, Daniel Loss, Seigo Tarucha
We measure and analyze noise-induced energy-fluctuations of spin qubits defined in quantum dots made of isotopically natural silicon. Combining Ramsey, time-correlation of single-shot measurements, and CPMG experiments, we cover the qubit noise power spectrum over a frequency range of nine orders of magnitude without any gaps. We find that the low-frequency noise spectrum is similar across three different devices suggesting that it is dominated by the hyperfine coupling to nuclei. The effects of charge noise are smaller, but not negligible, and are device dependent as confirmed from the noise cross-correlations. We also observe differences to spectra reported in GaAs [Phys. Rev. Lett. 118, 177702 (2017), Phys. Rev. Lett. 101, 236803 (2008)], which we attribute to the presence of the valley degree of freedom in silicon. Finally, we observe ({T}_{2}^{* }) to increase upon increasing the external magnetic field, which we speculate is due to the increasing field gradient of the micromagnet suppressing nuclear spin diffusion.
我们测量和分析了由同位素天然硅制成的量子点中定义的自旋量子比特的噪声诱导能量波动。结合Ramsey、单次测量的时间相关性和CPMG实验，我们在9个数量级的频率范围内覆盖了量子比特噪声功率谱，没有任何间隙。我们发现低频噪声谱在三种不同的器件上是相似的，这表明它是由与原子核的超精细耦合主导的。电荷噪声的影响较小，但不可忽略，并且从噪声相互关系中证实是器件相关的。我们还观察到与GaAs [Phys]中报道的光谱的差异。Rev. Lett. 118,177702 (2017), Phys。Rev. Lett. 101, 236803(2008)]，我们将其归因于硅中谷自由度的存在。最后，我们观察到({T}_{2}^{* })随着外磁场的增大而增大，我们推测这是由于微磁体的场梯度增大抑制了核自旋扩散。
{"title":"The origins of noise in the Zeeman splitting of spin qubits in natural-silicon devices","authors":"Juan S. Rojas-Arias, Yohei Kojima, Kenta Takeda, Peter Stano, Takashi Nakajima, Jun Yoneda, Akito Noiri, Takashi Kobayashi, Daniel Loss, Seigo Tarucha","doi":"10.1038/s41534-025-01150-6","DOIUrl":"https://doi.org/10.1038/s41534-025-01150-6","url":null,"abstract":"We measure and analyze noise-induced energy-fluctuations of spin qubits defined in quantum dots made of isotopically natural silicon. Combining Ramsey, time-correlation of single-shot measurements, and CPMG experiments, we cover the qubit noise power spectrum over a frequency range of nine orders of magnitude without any gaps. We find that the low-frequency noise spectrum is similar across three different devices suggesting that it is dominated by the hyperfine coupling to nuclei. The effects of charge noise are smaller, but not negligible, and are device dependent as confirmed from the noise cross-correlations. We also observe differences to spectra reported in GaAs [Phys. Rev. Lett. 118, 177702 (2017), Phys. Rev. Lett. 101, 236803 (2008)], which we attribute to the presence of the valley degree of freedom in silicon. Finally, we observe ({T}_{2}^{* }) to increase upon increasing the external magnetic field, which we speculate is due to the increasing field gradient of the micromagnet suppressing nuclear spin diffusion.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"27 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145705088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-06DOI: 10.1038/s41534-025-01152-4
Haoyu Sun, Pei Yu, Xu Zhou, Xiangyu Ye, Mengqi Wang, Zhaoxin Liu, Yuhang Guo, Wenzhao Liu, You Huang, Pengfei Wang, Fazhan Shi, Kangwei Xia, and Ya Wang
Advances in hybrid quantum systems and their precise control are pivotal for developing advanced quantum technologies. Two-dimensional (2D) materials with optically accessible spin defects have emerged as a promising platform for building integrated quantum spin systems due to their exceptional flexibility and scalability. However, experimentally realizing such systems and demonstrating their superiority remains challenging. Here, we present a hybrid spin system operating under ambient conditions, integrating boron vacancy ( $${{rm{V}}}_{{rm{B}}}^{-}$$VB− ) spins in 2D hexagonal boron nitride flakes with a single nitrogen vacancy (NV) center in 3D single-crystal diamonds. This combined system achieves full controllability and exhibits enhanced performance for nanoscale magnetic sensing, including an improved dynamic range. Moreover, we investigate the rich many-body spin dynamics within the hybrid system, which enables us to estimate the concentration of $${{rm{V}}}_{{rm{B}}}^{-}$$VB− spins. This work provides a critical foundation for advancing the development of 2D-3D integrated quantum spin systems.
混合量子系统及其精确控制的进展是发展先进量子技术的关键。由于具有优异的灵活性和可扩展性，具有光学可访问自旋缺陷的二维（2D）材料已成为构建集成量子自旋系统的有前途的平台。然而，通过实验实现这样的系统并证明其优越性仍然具有挑战性。在这里，我们提出了一个在环境条件下运行的混合自旋系统，将二维六方氮化硼片中的硼空位（$${{rm{V}}}_{{rm{B}}}^{-}$$ V B−）自旋与三维单晶金刚石中的单氮空位（NV）中心集成在一起。该组合系统实现了完全可控性，并表现出纳米级磁传感的增强性能，包括改进的动态范围。此外，我们研究了混合系统内的多体自旋动力学，这使我们能够估计$${{rm{V}}}_{{rm{B}}}^{-}$$ V B−自旋的浓度。这项工作为推进2D-3D集成量子自旋系统的发展提供了重要的基础。
{"title":"Room-temperature hybrid 2D-3D quantum spin system for enhanced magnetic sensing and many-body dynamics","authors":"Haoyu Sun, Pei Yu, Xu Zhou, Xiangyu Ye, Mengqi Wang, Zhaoxin Liu, Yuhang Guo, Wenzhao Liu, You Huang, Pengfei Wang, Fazhan Shi, Kangwei Xia, and Ya Wang","doi":"10.1038/s41534-025-01152-4","DOIUrl":"https://doi.org/10.1038/s41534-025-01152-4","url":null,"abstract":"Advances in hybrid quantum systems and their precise control are pivotal for developing advanced quantum technologies. Two-dimensional (2D) materials with optically accessible spin defects have emerged as a promising platform for building integrated quantum spin systems due to their exceptional flexibility and scalability. However, experimentally realizing such systems and demonstrating their superiority remains challenging. Here, we present a hybrid spin system operating under ambient conditions, integrating boron vacancy ( <jats:inline-formula> <jats:alternatives> <jats:tex-math>$${{rm{V}}}_{{rm{B}}}^{-}$$</jats:tex-math> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msubsup> <mml:mrow> <mml:mi>V</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>B</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> </jats:alternatives> </jats:inline-formula> ) spins in 2D hexagonal boron nitride flakes with a single nitrogen vacancy (NV) center in 3D single-crystal diamonds. This combined system achieves full controllability and exhibits enhanced performance for nanoscale magnetic sensing, including an improved dynamic range. Moreover, we investigate the rich many-body spin dynamics within the hybrid system, which enables us to estimate the concentration of <jats:inline-formula> <jats:alternatives> <jats:tex-math>$${{rm{V}}}_{{rm{B}}}^{-}$$</jats:tex-math> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msubsup> <mml:mrow> <mml:mi>V</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>B</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> </jats:alternatives> </jats:inline-formula> spins. This work provides a critical foundation for advancing the development of 2D-3D integrated quantum spin systems.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"21 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145680172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-05DOI: 10.1038/s41534-025-01095-w
Woo Chang Chung, Daniel C. Cole, Pranav Gokhale, Eric B. Jones, Kevin W. Kuper, David Mason, Victory Omole, Alexander G. Radnaev, Rich Rines, Mariesa H. Teo, Matt J. Bedalov, Matt Blakely, Peter D. Buttler, Caitlin Carnahan, Frederic T. Chong, Palash Goiporia, Bettina Heim, Garrett T. Hickman, Ryan A. Jones, Pradnya Khalate, Jin-Sung Kim, Martin T. Lichtman, Stephanie Lee, Nathan A. Neff-Mallon, Thomas W. Noel, Mark Saffman, Efrat Shabtai, Bharath Thotakura, Teague Tomesh, Angela K. Tucker
We report on the fault-tolerant operation of logical qubits on a neutral atom quantum computer, with logical performance surpassing physical performance for multiple circuits including Bell state preparation (12x error reduction), random circuits (15x), and a prototype Anderson Impurity Model ground state solver for materials science applications (up to 6x, non-fault-tolerantly). The logical qubits are implemented via the [[4, 2, 2]] code (C 4 ). Our work constitutes the first complete realization of the benchmarking protocol proposed by Gottesman 2016 demonstrating results consistent with fault tolerance. In light of recent advances on applying concatenated C 4 /C 6 detection codes to achieve error correction with high code rates and thresholds, our work can be regarded as a building block towards a practical scheme for fault tolerant quantum computation. Our demonstration of a materials science application with logical qubits particularly demonstrates the immediate value of these techniques on current experiments.
{"title":"Fault-tolerant operation and materials science with neutral atom logical qubits","authors":"Woo Chang Chung, Daniel C. Cole, Pranav Gokhale, Eric B. Jones, Kevin W. Kuper, David Mason, Victory Omole, Alexander G. Radnaev, Rich Rines, Mariesa H. Teo, Matt J. Bedalov, Matt Blakely, Peter D. Buttler, Caitlin Carnahan, Frederic T. Chong, Palash Goiporia, Bettina Heim, Garrett T. Hickman, Ryan A. Jones, Pradnya Khalate, Jin-Sung Kim, Martin T. Lichtman, Stephanie Lee, Nathan A. Neff-Mallon, Thomas W. Noel, Mark Saffman, Efrat Shabtai, Bharath Thotakura, Teague Tomesh, Angela K. Tucker","doi":"10.1038/s41534-025-01095-w","DOIUrl":"https://doi.org/10.1038/s41534-025-01095-w","url":null,"abstract":"We report on the fault-tolerant operation of logical qubits on a neutral atom quantum computer, with logical performance surpassing physical performance for multiple circuits including Bell state preparation (12x error reduction), random circuits (15x), and a prototype Anderson Impurity Model ground state solver for materials science applications (up to 6x, non-fault-tolerantly). The logical qubits are implemented via the [[4, 2, 2]] code (C <jats:sub>4</jats:sub> ). Our work constitutes the first complete realization of the benchmarking protocol proposed by <jats:italic>Gottesman 2016</jats:italic> demonstrating results consistent with fault tolerance. In light of recent advances on applying concatenated C <jats:sub>4</jats:sub> /C <jats:sub>6</jats:sub> detection codes to achieve error correction with high code rates and thresholds, our work can be regarded as a building block towards a practical scheme for fault tolerant quantum computation. Our demonstration of a materials science application with logical qubits particularly demonstrates the immediate value of these techniques on current experiments.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"35 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145680055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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