npj Quantum Information最新文献_第6页

Fundamental causal bounds of quantum random access memories 量子随机存取存储器的基本因果界限

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-07-23 DOI: 10.1038/s41534-024-00848-3

Yunfei Wang, Yuri Alexeev, Liang Jiang, Frederic T. Chong, Junyu Liu

{"title":"Fundamental causal bounds of quantum random access memories","authors":"Yunfei Wang, Yuri Alexeev, Liang Jiang, Frederic T. Chong, Junyu Liu","doi":"10.1038/s41534-024-00848-3","DOIUrl":"https://doi.org/10.1038/s41534-024-00848-3","url":null,"abstract":"Our study evaluates the limitations and potentials of Quantum Random Access Memory (QRAM) within the principles of quantum physics and relativity. QRAM is crucial for advancing quantum algorithms in fields like linear algebra and machine learning, purported to efficiently manage large data sets with ({{{mathcal{O}}}}(log N)) circuit depth. However, its scalability is questioned when considering the relativistic constraints on qubits interacting locally. Utilizing relativistic quantum field theory and Lieb–Robinson bounds, we delve into the causality-based limits of QRAM. Our investigation introduces a feasible QRAM model in hybrid quantum acoustic systems, capable of supporting a significant number of logical qubits across different dimensions-up to ~107 in 1D, ~1015 to ~1020 in 2D, and ~1024 in 3D, within practical operation parameters. This analysis suggests that relativistic causality principles could universally influence quantum computing hardware, underscoring the need for innovative quantum memory solutions to navigate these foundational barriers, thereby enhancing future quantum computing endeavors in data science.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"31 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141755324","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}

引用次数: 0

The silicon vacancy centers in SiC: determination of intrinsic spin dynamics for integrated quantum photonics 碳化硅中的硅空位中心：确定集成量子光子学的内在自旋动力学

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-07-23 DOI: 10.1038/s41534-024-00861-6

Di Liu, Florian Kaiser, Vladislav Bushmakin, Erik Hesselmeier, Timo Steidl, Takeshi Ohshima, Nguyen Tien Son, Jawad Ul-Hassan, Öney O. Soykal, Jörg Wrachtrup

{"title":"The silicon vacancy centers in SiC: determination of intrinsic spin dynamics for integrated quantum photonics","authors":"Di Liu, Florian Kaiser, Vladislav Bushmakin, Erik Hesselmeier, Timo Steidl, Takeshi Ohshima, Nguyen Tien Son, Jawad Ul-Hassan, Öney O. Soykal, Jörg Wrachtrup","doi":"10.1038/s41534-024-00861-6","DOIUrl":"https://doi.org/10.1038/s41534-024-00861-6","url":null,"abstract":"The negatively charged silicon vacancy center (({{rm{V}}}_{{rm{Si}}}^{-})) in silicon carbide (SiC) is an emerging color center for quantum technology covering quantum sensing, communication, and computing. Yet, limited information currently available on the internal spin-optical dynamics of these color centers prevents us from achieving the optimal operation conditions and reaching the maximum performance especially when integrated within quantum photonics. Here, we establish all the relevant intrinsic spin dynamics of the ({{rm{V}}}_{{rm{Si}}}^{-}) center at cubic lattice site (V2) in 4H-SiC by an in-depth electronic fine structure modeling including the intersystem-crossing and deshelving mechanisms. With carefully designed spin-dependent measurements, we obtain all the previously unknown spin-selective radiative and non-radiative decay rates. To showcase the relevance of our work for integrated quantum photonics, we use the obtained rates to propose a realistic implementation of time-bin entangled multi-photon GHZ and cluster state generation. We find that up to three-photon GHZ or cluster states are readily within reach using the existing nanophotonic cavity technology.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"43 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141755325","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}

引用次数: 0

Low charge noise quantum dots with industrial CMOS manufacturing 利用工业 CMOS 制造低电荷噪声量子点

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-07-19 DOI: 10.1038/s41534-024-00864-3

A. Elsayed, M. M. K. Shehata, C. Godfrin, S. Kubicek, S. Massar, Y. Canvel, J. Jussot, G. Simion, M. Mongillo, D. Wan, B. Govoreanu, I. P. Radu, R. Li, P. Van Dorpe, K. De Greve

{"title":"Low charge noise quantum dots with industrial CMOS manufacturing","authors":"A. Elsayed, M. M. K. Shehata, C. Godfrin, S. Kubicek, S. Massar, Y. Canvel, J. Jussot, G. Simion, M. Mongillo, D. Wan, B. Govoreanu, I. P. Radu, R. Li, P. Van Dorpe, K. De Greve","doi":"10.1038/s41534-024-00864-3","DOIUrl":"https://doi.org/10.1038/s41534-024-00864-3","url":null,"abstract":"Silicon spin qubits are promising candidates for scalable quantum computers, due to their coherence and compatibility with CMOS technology. Advanced industrial processes ensure wafer-scale uniformity and high device yield, but traditional transistor processes cannot be directly transferred to qubit structures. To leverage the micro-electronics industry expertise, we customize a 300 mm wafer fabrication line for silicon MOS qubit integration. With careful optimization of the gate stack, we report uniform quantum dot operation at the Si/SiO2 interface at mK temperature. We measure a record-low average noise with a value of 0.61 ({rm{mu }}{rm{eVH}}{{rm{z}}}^{-0.5}) at 1 Hz and even below 0.1 ({rm{mu }}{rm{eVH}}{{rm{z}}}^{-0.5}) for some operating conditions. Statistical analysis of the charge noise measurements show that the noise source can be described by a two-level fluctuator model. This reproducible low noise level, in combination with uniform operation of our quantum dots, marks CMOS manufactured spin qubits as a mature platform towards scalable high-fidelity qubits.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"17 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141730697","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}

引用次数: 0

Charge-parity switching effects and optimisation of transmon-qubit design parameters 电荷奇偶性开关效应与跨子-量子比特设计参数的优化

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-07-15 DOI: 10.1038/s41534-024-00860-7

Miha Papič, Jani Tuorila, Adrian Auer, Inés de Vega, Amin Hosseinkhani

{"title":"Charge-parity switching effects and optimisation of transmon-qubit design parameters","authors":"Miha Papič, Jani Tuorila, Adrian Auer, Inés de Vega, Amin Hosseinkhani","doi":"10.1038/s41534-024-00860-7","DOIUrl":"https://doi.org/10.1038/s41534-024-00860-7","url":null,"abstract":"Enhancing the performance of noisy quantum processors requires improving our understanding of error mechanisms and the ways to overcome them. A judicious selection of qubit design parameters plays a pivotal role in improving the performance of quantum processors. In this study, we identify optimal ranges for qubit design parameters, grounded in comprehensive noise modeling. To this end, we also analyze the effect of a charge-parity switch caused by quasiparticles on a two-qubit gate. Due to the utilization of the second excited state of a transmon, where the charge dispersion is significantly larger, a charge-parity switch will affect the conditional phase of the two-qubit gate. We derive an analytical expression for the infidelity of a diabatic controlled-Z gate and see effects of similar magnitude in adiabatic controlled-phase gates in the tunable coupler architecture. Moreover, we show that the effect of a charge-parity switch can be the dominant quasiparticle-related error source of a two-qubit gate. We also demonstrate that charge-parity switches induce a residual longitudinal interaction between qubits in a tunable-coupler circuit. Furthermore, we introduce a performance metric for quantum circuit execution, encompassing the fidelity and number of single- and two-qubit gates in an algorithm, as well as the state preparation fidelity. This comprehensive metric, coupled with a detailed noise model, enables us to determine an optimal range for the qubit design parameters, as confirmed by numerical simulation. Our systematic analysis offers insights and serves as a guiding framework for the development of the next generation of transmon-based quantum processors.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"9 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141625104","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}

引用次数: 0

Contextual quantum metrology 语境量子计量学

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-07-04 DOI: 10.1038/s41534-024-00862-5

Jeongwoo Jae, Jiwon Lee, M. S. Kim, Kwang-Geol Lee, Jinhyoung Lee

引用次数: 0

Shortcut to multipartite entanglement generation: A graph approach to boson subtractions 多方纠缠生成的捷径：玻色子减法的图方法

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-07-03 DOI: 10.1038/s41534-024-00845-6

Seungbeom Chin, Yong-Su Kim, Marcin Karczewski

引用次数: 0

Approximate encoding of quantum states using shallow circuits 利用浅层电路对量子态进行近似编码

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-07-02 DOI: 10.1038/s41534-024-00858-1

Matan Ben-Dov, David Shnaiderov, Adi Makmal, Emanuele G. Dalla Torre

引用次数: 0

Experimental error suppression in Cross-Resonance gates via multi-derivative pulse shaping 通过多衍生脉冲整形抑制交叉谐振门的实验误差

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-07-02 DOI: 10.1038/s41534-024-00863-4

Boxi Li, Tommaso Calarco, Felix Motzoi

{"title":"Experimental error suppression in Cross-Resonance gates via multi-derivative pulse shaping","authors":"Boxi Li, Tommaso Calarco, Felix Motzoi","doi":"10.1038/s41534-024-00863-4","DOIUrl":"https://doi.org/10.1038/s41534-024-00863-4","url":null,"abstract":"While quantum circuits are reaching impressive widths in the hundreds of qubits, their depths have not been able to keep pace. In particular, cloud computing gates on multi-qubit, fixed-frequency superconducting chips continue to hover around the 1% error range, contrasting with the progress seen on carefully designed two-qubit chips, where error rates have been pushed towards 0.1%. Despite the strong impetus and a plethora of research, experimental demonstration of error suppression on these multi-qubit devices remains challenging, primarily due to the wide distribution of qubit parameters and the demanding calibration process required for advanced control methods. Here, we achieve this goal, using a simple control method based on multi-derivative, multi-constraint pulse shaping, which acts simultaneously against multiple error sources. Our approach establishes a two to fourfold improvement on the default calibration scheme, demonstrated on four qubits on the IBM Quantum Platform with limited and intermittent access, enabling these large-scale fixed-frequency systems to fully take advantage of their superior coherence times. The achieved CNOT fidelities of 99.7(1)% on those publically available qubits come from both coherent control error suppression and accelerated gate time.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"59 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489604","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}

引用次数: 0

Calibration-independent bound on the unitarity of a quantum channel with application to a frequency converter 量子信道单位性的校准无关约束，应用于频率转换器

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-06-22 DOI: 10.1038/s41534-024-00859-0

Matthias Bock, Pavel Sekatski, Jean-Daniel Bancal, Stephan Kucera, Tobias Bauer, Nicolas Sangouard, Christoph Becher, Jürgen Eschner

{"title":"Calibration-independent bound on the unitarity of a quantum channel with application to a frequency converter","authors":"Matthias Bock, Pavel Sekatski, Jean-Daniel Bancal, Stephan Kucera, Tobias Bauer, Nicolas Sangouard, Christoph Becher, Jürgen Eschner","doi":"10.1038/s41534-024-00859-0","DOIUrl":"https://doi.org/10.1038/s41534-024-00859-0","url":null,"abstract":"We report on a method to certify a unitary operation with the help of source and measurement apparatuses whose calibration throughout the certification process needs not be trusted. As in the device-independent paradigm our certification method relies on a Bell test and requires no assumption on the underlying Hilbert space dimension, but it removes the need for high detection efficiencies by including the single additional assumption that non-detected events are independent of the measurement settings. The relevance of the proposed method is demonstrated experimentally by bounding the unitarity of a quantum frequency converter. The experiment starts with the heralded creation of a maximally entangled two-qubit state between a single 40Ca+ ion and a 854 nm photon. Entanglement preserving frequency conversion to the telecom band is then realized with a non-linear waveguide embedded in a Sagnac interferometer. The resulting ion-telecom photon entangled state is assessed by means of a Bell-CHSH test from which the quality of the frequency conversion is quantified. We demonstrate frequency conversion with an average certified fidelity of ≥84% and an efficiency ≥3.1 × 10−6 at a confidence level of 99%. This ensures the suitability of the converter for integration in quantum networks from a trustful characterization procedure.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"26 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141439810","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}

引用次数: 0

A benchmarking study of quantum algorithms for combinatorial optimization 组合优化量子算法基准研究

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-06-22 DOI: 10.1038/s41534-024-00856-3

Krishanu Sankar, Artur Scherer, Satoshi Kako, Sam Reifenstein, Navid Ghadermarzy, Willem B. Krayenhoff, Yoshitaka Inui, Edwin Ng, Tatsuhiro Onodera, Pooya Ronagh, Yoshihisa Yamamoto

{"title":"A benchmarking study of quantum algorithms for combinatorial optimization","authors":"Krishanu Sankar, Artur Scherer, Satoshi Kako, Sam Reifenstein, Navid Ghadermarzy, Willem B. Krayenhoff, Yoshitaka Inui, Edwin Ng, Tatsuhiro Onodera, Pooya Ronagh, Yoshihisa Yamamoto","doi":"10.1038/s41534-024-00856-3","DOIUrl":"https://doi.org/10.1038/s41534-024-00856-3","url":null,"abstract":"We study the performance scaling of three quantum algorithms for combinatorial optimization: measurement-feedback coherent Ising machines (MFB-CIM), discrete adiabatic quantum computation (DAQC), and the Dürr–Høyer algorithm for quantum minimum finding (DH-QMF) that is based on Grover’s search. We use MaxCut problems as a reference for comparison, and time-to-solution (TTS) as a practical measure of performance for these optimization algorithms. For each algorithm, we analyze its performance in solving two types of MaxCut problems: weighted graph instances with randomly generated edge weights attaining 21 equidistant values from −1 to 1; and randomly generated Sherrington–Kirkpatrick (SK) spin glass instances. We empirically find a significant performance advantage for the studied MFB-CIM in comparison to the other two algorithms. We empirically observe a sub-exponential scaling for the median TTS for the MFB-CIM, in comparison to the almost exponential scaling for DAQC and the proven (widetilde{{{{mathcal{O}}}}}left(sqrt{{2}^{n}}right)) scaling for DH-QMF. We conclude that the MFB-CIM outperforms DAQC and DH-QMF in solving MaxCut problems.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"60 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141439815","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}

引用次数: 0