检索结果-内蒙古大学图书馆

Verifiable quantum secure modulo summation

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Hayashi, Masahito Koshiba, Takeshi Graduate School of Mathematics Nagoya University Japan Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen China Center for Quantum Computing Peng Cheng Laboratory Shenzhen China Center for Quantum Technologies National University of Singapore Singapore Faculty of Education and Integrated Arts and Sciences Waseda University Tokyo Japan

We propose a new cryptographic task, which we call verifiable quantum secure modulo summation. Secure modulo summation is a calculation of modulo summation Y1 + . . . + Ym when m players have their individual variables Y1, . . ., Ym with keeping the secrecy of the individual variables. However, the conventional method for secure modulo summation uses so many secret communication channels. We say that a quantum protocol for secure modulo summation is quantum verifiable secure modulo summation when it can verify the desired secrecy condition. If we combine device independent quantum key distribution, it is possible to verify such secret communication channels. However, it consumes so many steps. To resolve this problem, using quantum systems, we propose a more direct method to realize secure modulo summation with verification. To realize this protocol, we propose modulo zero-sum randomness as another new concept, and show that secure modulo summation can be realized by using modulo zero-sum randomness. Then, we construct a verifiable quantum protocol method to generate modulo zero-sum randomness. This protocol can be verified only with minimum requirements. Copyright © 2019, The Authors. All rights reserved.

关键词： Random processes

Optimal Bounds on State Transfer Under quantum Channels with Application to Spin System engineering

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Zheng, Wenqiang Wang, Hengyan Xin, Tao Nie, Xinfang Lu, Dawei Li, Jun Collaborative Innovation Center for Bio-Med Physics Information Technology College of Science Zhejiang University of Technology Hangzhou310023 China Department of Physics Zhejiang University of Science and Technology Hangzhou310023 China Shenzhen Institute for Quantum Science and Engineering Department of Physics Southern University of Science and Technology Shenzhen518055 China Center for Quantum Computing Peng Cheng Laboratory Shenzhen518055 China Shenzhen Key Laboratory of Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China

Modern applications of quantum control in quantum information science and technology require the precise characterization of quantum states and quantum channels. In particular, high-performance quantum state engineering often demands that quantum states are transferred with optimal efficiency via realizable controlled evolution, the latter often modeled by quantum channels. When an appropriate quantum control model for an interested system is constructed, the exploration of optimal bounds on state transfer for the underlying quantum channel is then an important task. In this work, we analyze the state transfer efficiency problem for different class of quantum channels, including unitary, mixed unitary and Markovian. We then apply the theory to nuclear magnetic resonance (NMR) experiments. We show that two most commonly used control techniques in NMR, namely gradient field control and phase cycling, can be described by mixed unitary channels. Then we show that employing mixed unitary channels does not extend the unitarily accessible region of states. Also, we present a strategy of optimal experiment design, which incorporates coherent radio-frequency field control, gradient field control and phase cycling, aiming at maximizing state transfer efficiency and meanwhile minimizing the number of experiments required. Finally, we perform pseudopure state preparation experiments on two- and three-spin systems, in order to test the bound theory and to demonstrate the usefulness of non-unitary control means. Copyright © 2019, The Authors. All rights reserved.

关键词： Spin dynamics

Building a fault-tolerant quantum computer using concatenated cat codes

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Chamberland, Christopher Noh, Kyungjoo Arrangoiz-Arriola, Patricio Campbell, Earl T. Hann, Connor T. Iverson, Joseph Putterman, Harald Bohdanowicz, Thomas C. Flammia, Steven T. Keller, Andrew Refael, Gil Preskill, John Jiang, Liang Safavi-Naeini, Amir H. Painter, Oskar Brandão, Fernando G.S.L. AWS Center for Quantum Computing PasadenaCA91125 United States IQIM California Institute of Technology PasadenaCA91125 United States Department of Physics Yale University New HavenCT06511 United States Pritzker School of Molecular Engineering The University of Chicago IL60637 United States Department of Applied Physics Ginzton Laboratory Stanford University StanfordCA94305 United States

We present a comprehensive architectural analysis for a proposed fault-tolerant quantum computer based on cat codes concatenated with outer quantum error-correcting codes. For the physical hardware, we propose a system of acoustic resonators coupled to superconducting circuits with a two-dimensional layout. Using estimated physical parameters for the hardware, we perform a detailed error analysis of measurements and gates, including CNOT and Toffoli gates. Having built a realistic noise model, we numerically simulate quantum error correction when the outer code is either a repetition code or a thin rectangular surface code. Our next step toward universal fault-tolerant quantum computation is a protocol for fault-tolerant Toffoli magic state preparation that significantly improves upon the fidelity of physical Toffoli gates at very low qubit cost. To achieve even lower overheads, we devise a new magic-state distillation protocol for Toffoli states. Combining these results together, we obtain realistic full-resource estimates of the physical error rates and overheads needed to run useful fault-tolerant quantum algorithms. We find that with around 1,000 superconducting circuit components, one could construct a fault-tolerant quantum computer that can run circuits which are currently intractable for classical computers. Hardware with 18,000 superconducting circuit components, in turn, could simulate the Hubbard model in a regime beyond the reach of classical computing. © 2020, CC BY.

关键词： Error correction

Efficient Verification of Hypergraph States

学校读者我要写书评

暂无评论

Physical Review Applied 2019年第5期12卷 054047-054047页

作者： Huangjun Zhu Masahito Hayashi Department of Physics and Center for Field Theory and Particle Physics Fudan University Shanghai 200433 China State Key Laboratory of Surface Physics Fudan University Shanghai 200433 China Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai 200433 China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093 China Institute for Theoretical Physics University of Cologne Cologne 50937 Germany Graduate School of Mathematics Nagoya University Nagoya 464-8602 Japan Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen 518055 China Center for Quantum Computing Peng Cheng Laboratory Shenzhen 518000 China Centre for Quantum Technologies National University of Singapore 3 Science Drive 2 117542 Singapore

Graph states and hypergraph states are of wide interest in quantum information processing and foundational studies. Efficient verification of these states is a key to various applications. Here we propose a simple method for verifying hypergraph states, which requires only two distinct Pauli measurements for each party, yet its efficiency is comparable to the best strategy based on entangling measurements. For a given state, the overhead is bounded by the chromatic number and degree of the underlying hypergraph. Our protocol is dramatically more efficient than all previous protocols based on local measurements, including tomography and direct-fidelity estimation. It enables the verification of hypergraph states and genuine multipartite entanglement of thousands of qubits. The protocol can also be generalized to the adversarial scenario, while achieving almost the same efficiency. This merit is particularly appealing to demonstrating blind measurement-based quantum computation and quantum supremacy.

关键词： Entanglement detection Measurement-based quantum computing quantum benchmarking quantum information processing quantum networks quantum tomography Resource theories Graph theory

Enhancement of optomechanically induced sum sideband using parametric interactions

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Li, Wen-An Huang, Guang-Yao School of Physics and Electronic Engineering Guangzhou University Guangzhou510006 China Institute for Quantum Information & State Key Laboratory of High Performance Computing College of Computer National University of Defense Technology Changsha410073 China

We theoretically study radiation pressure induced generation of the frequency components at the sum sideband in an optomechanical system containing an optical parametric amplifier (OPA). It is shown that an OPA inside a cavity can considerably enhance the amplitude of sum sideband even with low power input fields. We find a new matching condition for the upper sum sideband generation. The height and width of the new peak can be adjusted by the nonlinear gain of the OPA. Furthermore, the lower sum sideband generation can be enhanced with several orders of magnitude by tuning the nonlinear gain parameter and the phase of the field pumping the OPA. The enhanced sum sideband may have potential applications to the manipulation of light in a on-chip optomechanical device and the sensitively sensing for precision measurement in the weak optomechanical coupling regime. Copyright © 2019, The Authors. All rights reserved.

关键词： Optical parametric amplifiers

Communication cost of quantum channels

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Yang, Yuxiang Chiribella, Giulio Hayashi, Masahito Institute for Theoretical Physics ETH Zurich Department of Computer Science University of Hong Kong Pokfulam Road Hong Kong Department of Computer Science University of Oxford Parks Road Oxford United Kingdom HKU Shenzhen Institute of Research and Innovation Kejizhong 2nd Road Shenzhen China Perimeter Institute For Theoretical Physics 31 Caroline Street North WaterlooONN2L 2Y5 Canada Graduate School of Mathematics Nagoya University Nagoya464-8602 Japan Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China Center for Quantum Computing Peng Cheng Laboratory Shenzhen518000 China Centre for Quantum Technologies National University of Singapore 3 Science Drive 2 117542 Singapore

In distributed computing, it is common for a server to execute a program of a remote client, consuming the minimum amount of communication. We extend such a setting to the quantum regime and consider the task of communicating quantum channels for the purpose of executing them a given number of times. We derive a general lower bound for the amount of required communication. The bound shows that the amount of required communication is positively correlated to the performance of the channels in quantum metrology. We also propose a protocol achieving the bound for a type of channels. Copyright © 2020, The Authors. All rights reserved.

关键词： quantum entanglement

A platform for high performance photon correlation measurements

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Zadeh, Iman Esmaeil Los, Johannes W.N. Gourgues, Ronan B.M. Chang, Jin Elshaari, Ali W. Zichi, Julien van Staaden, Yuri J. Swens, Jeroen Kalhor, Nima Guardiani, Antonio Meng, Yun Zou, Kai Dobrovolskiy, Sergiy Fognini, Andreas W. Schaart, Dennis R. Dalacu, Dan Poole, Philip J. Reimer, Michael E. Hu, Xiaolong Pereira, Silvania F. Zwiller, Val Dorenbos, Sander N. Optics Research Group ImPhys Department Faculty of Applied Sciences Delft University of Technology Delft2628 CJ Netherlands Single Quantum B.V. Delft2628 CJ Netherlands Optics Research Group Imphys Department Faculty of Applied Sciences Delft University of Technology Delft2628 CJ Netherlands Stockholm106 91 Sweden School of Precision Instrument and Optoelectronic Engineering Tianjin University Tianjin300072 China Key Laboratory of Optoelectronic Information Science and Technology Ministry of Education Tianjin300072 China Medical Physics & Technology Radiation Science & Technology Department Faculty of Applied Sciences Delft University of Technology National Research Council of Canada OttawaONK1A 0R6 Canada Institute for Quantum Computing Department of Electrical & Computer Engineering University of Waterloo WaterlooONN2L 3G1 Canada

A broad range of scientific and industrial disciplines require precise optical measurements at very low light levels. Single-photon detectors combining high efficiency and high time resolution are pivotal in such experiments. By using relatively thick films of NbTiN (8-11 nm) and improving the pattern fidelity of the nano-structure of the superconducting nanowire single-photon detectors (SNSPD), we fabricated devices demonstrating superior performance over all previously reported detectors in the combination of efficiency and time resolution. Our findings prove that small variations in the nanowire width, in the order of a few nanometers, can lead to a significant penalty on their temporal response. Addressing these issues, we consistently achieved high time resolution (best device 7.7 ps, other devices ∼10-16 ps) simultaneously with high system detection efficiencies (80 − 90%) in the wavelength range of 780-1000 nm, as well as in the telecom bands (1310-1550 nm). The use of thicker films allowed us to fabricate large-area multi-pixel devices with homogeneous pixel performance. We first fabricated and characterized a 100 × 100 µm2 16-pixel detector and showed there was little variation among individual pixels. Additionally, to showcase the power of our platform, we fabricated and characterized 4-pixel multimode fiber-coupled detectors and carried out photon correlation experiments on a nanowire quantum dot resulting in g2(0) values lower than 0.04. The multi-pixel detectors alleviate the need for beamsplitters and can be used for higher order correlations with promising prospects not only in the field of quantum optics, but also in bio-imaging applications, such as fluorescence microscopy and positron emission tomography. Copyright © 2020, The Authors. All rights reserved.

关键词： quantum optics

quantum teleportation of physical qubits into logical code-spaces

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Luo, Yi-Han Chen, Ming-Cheng Erhard, Manuel Zhong, Han-Sen Wu, Dian Tang, Hao-Yang Zhao, Qi Wang, Xi-Lin Fujii, Keisuke Li, Li Liu, Nai-Le Nemoto, Kae Munro, William J. Lu, Chao-Yang Zeilinger, Anton Pan, Jian-Wei Hefei National Laboratory for Physical Sciences at Microscale Department of Modern Physics University of Science and Technology of China Hefei230026 China CAS Centre for Excellence in Quantum Information and Quantum Physics Hefei230026 China Boltzmanngasse 3 ViennaA-1090 Austria Faculty of Physics University of Vienna ViennaA-1090 Austria Graduate School of Engineering Science Division of Advanced Electronics and Optical Science Quantum Computing Group 1-3 Machikaneyama Toyonaka Osaka560-8531 Japan NTT Basic Research Laboratories NTT Research Center for Theoretical Quantum Physics NTT Corporation 3-1 Morinosato-Wakamiya Atsugi-shi Kanagawa243-0198 Japan National Institute of Informatics 2-1-2 Hitotsubashi Chiyoda-ku Tokyo101-8430 Japan

quantum error correction is an essential tool for reliably performing tasks for processing quantum information on a large scale. However, integration into quantum circuits to achieve these tasks is problematic when one realizes that non-transverse operations, which are essential for universal quantum computation, lead to the spread of errors. quantum gate teleportation has been proposed as an elegant solution for this. Here, one replaces these fragile, non-transverse inline gates with the generation of specific, highly entangled offline resource states that can be teleported into the circuit to implement the non-transverse gate. As the first important step, we create a maximally entangled state between a physical and an error-correctable logical qubit and use it as a teleportation resource. We then demonstrate the teleportation of quantum information encoded on the physical qubit into the error-corrected logical qubit with fidelities up to 0.786. Our scheme can be designed to be fully fault-tolerant so that it can be used in future large-scale quantum technologies. Copyright © 2020, The Authors. All rights reserved.

关键词： quantum entanglement

quantum and classical query complexities for generalized Simon’s problem

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Wu, Zhenggang Qiu, Daowen Tan, Jiawei Li, Hao Cai, Guangya Institute of Quantum Computing and Computer Theory School of Computer Science and Engineering Sun Yat-sen University Guangzhou510006 China The Guangdong Key Laboratory of Information Security Technology Sun Yat-sen University 510006 China

Simon’s problem is an essential example demonstrating the faster speed of quantum computers than classical computers for solving some problems. The optimal separation between exact quantum and classical query complexities for Simon’s problem has been proved by Cai & Qiu. Generalized Simon’s problem can be described as follows. Given a function f : {0, 1}n → {0, 1}m, with the property that there is some unknown hidden subgroup S such that f(x) = f(y) iff x ⊕ y ∈ S, for any x, y ∈ {0, 1}n, where |S| = 2k for some 0 ≤ k ≤ n. The goal is to find S. For the case of k = 1, it is Simon’s problem. In this paper, we propose an exact quantum algorithm with O(n − k) queries and an non-adaptive deterministic classical algorithm with O(k√2n−k) queries for solving the generalized Simon’s problem. Also, we prove that their lower bounds are Ω(n − k) and Ω(√k2n−k), respectively. Therefore, we obtain a tight exact quantum query complexity Θ(n − k) and an almost tight non-adaptive classical deterministic query complexities Ω(√k2n−k) ∼ O(k√2n−k) for this problem. Copyright © 2019, The Authors. All rights reserved.

关键词： quantum theory