arXiv: Quantum Physics最新文献_第3页

Noisy quantum input loophole in measurement-device-independent entanglement witnesses 测量设备无关纠缠目击中的噪声量子输入漏洞

arXiv: Quantum Physics Pub Date : 2020-12-16 DOI: 10.1103/PhysRevA.104.012429

Kornikar Sen, Chirag Srivastava, S. Mal, Aditi Sen(De), U. Sen

{"title":"Noisy quantum input loophole in measurement-device-independent entanglement witnesses","authors":"Kornikar Sen, Chirag Srivastava, S. Mal, Aditi Sen(De), U. Sen","doi":"10.1103/PhysRevA.104.012429","DOIUrl":"https://doi.org/10.1103/PhysRevA.104.012429","url":null,"abstract":"Entanglement witnesses form an effective method to locally detect entanglement in the laboratory without having the prior knowledge of the full density matrix. However, separable states can be erroneously indicated as entangled in such detections in the presence of wrong measurements or loss in detectors. Measurement-device-independent entanglement witnesses (MDI-EWs) never detect fake entanglement even under wrong measurements and for a particular kind of lossy detectors. A crucial assumption in the case of faithful detection of entanglement employing MDI-EWs is that the preparation devices producing \"quantum inputs\" - which are inputs additional to the quantum state whose entanglement is to be detected - are perfect and there is no noise during their transmission. Here, we relax these assumptions and provide a general framework for studying the effect of noise on the quantum inputs, invoking uniform and non-uniform noise models. We derive sufficient conditions on the uniform noisy map for retaining the characteristic of MDI-EWs. We find that in the context of non-uniform and entangling noise, fake entanglement detection is possible even by MDI-EWs. We also investigate various paradigmatic models of local noise and find conditions of revealing entanglement in the class of Werner states.","PeriodicalId":8484,"journal":{"name":"arXiv: Quantum Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78421676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Multiparameter quantum metrology with postselection measurements 具有后选择测量的多参数量子计量

arXiv: Quantum Physics Pub Date : 2020-12-15 DOI: 10.1063/5.0024555

Le Bin Ho, Yasushi Kondo

引用次数: 6

Observations of On-Demand Quantum Correlation Using Poisson-Distributed Photon Pairs 用泊松分布光子对观察按需量子相关

arXiv: Quantum Physics Pub Date : 2020-12-15 DOI: 10.21203/rs.3.rs-125559/v1

Sangbae Kim, B. Ham

引用次数: 2

Trapped bosons, thermodynamic limit, and condensation: A study in the framework of resolvent algebras 捕获玻色子、热力学极限和凝聚:在求解代数框架下的研究

arXiv: Quantum Physics Pub Date : 2020-12-15 DOI: 10.1063/5.0042830

D. Bahns, D. Buchholz

引用次数: 4

Noise-Assisted Quantum Autoencoder 噪声辅助量子自编码器

arXiv: Quantum Physics Pub Date : 2020-12-15 DOI: 10.1103/PhysRevApplied.15.054012

Chenfeng Cao, Xin Wang

{"title":"Noise-Assisted Quantum Autoencoder","authors":"Chenfeng Cao, Xin Wang","doi":"10.1103/PhysRevApplied.15.054012","DOIUrl":"https://doi.org/10.1103/PhysRevApplied.15.054012","url":null,"abstract":"Quantum autoencoder is an efficient variational quantum algorithm for quantum data compression. However, previous quantum autoencoders fail to compress and recover high-rank mixed states. In this work, we discuss the fundamental properties and limitations of the standard quantum autoencoder model in more depth, and provide an information-theoretic solution to its recovering fidelity. Based on this understanding, we present a noise-assisted quantum autoencoder algorithm to go beyond the limitations, our model can achieve high recovering fidelity for general input states. Appropriate noise channels are used to make the input mixedness and output mixedness consistent, the noise setup is determined by measurement results of the trash system. Compared with the original quantum autoencoder model, the measurement information is fully used in our algorithm. In addition to the circuit model, we design a (noise-assisted) adiabatic model of quantum autoencoder that can be implemented on quantum annealers. We verified the validity of our methods through compressing the thermal states of transverse field Ising model. For pure state ensemble compression, we also introduce a projected quantum autoencoder algorithm. Our models have wide applications for quantum data compression on near-term quantum devices.","PeriodicalId":8484,"journal":{"name":"arXiv: Quantum Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80745243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 40

Sampling and the complexity of nature 采样和自然的复杂性

arXiv: Quantum Physics Pub Date : 2020-12-14 DOI: 10.17169/REFUBIUM-28790

D. Hangleiter

{"title":"Sampling and the complexity of nature","authors":"D. Hangleiter","doi":"10.17169/REFUBIUM-28790","DOIUrl":"https://doi.org/10.17169/REFUBIUM-28790","url":null,"abstract":"Randomness is an intrinsic feature of quantum theory. The outcome of any quantum measurement will be random, sampled from a probability distribution that is defined by the measured quantum state. The task of sampling from a prescribed probability distribution is therefore a natural technological application of quantum devices. In the research presented in this thesis, I investigate the complexity-theoretic and physical foundations of quantum sampling algorithms. I assess the computational power of natural quantum simulators and close loopholes in the complexity-theoretic argument for the classical intractability of quantum samplers (Part I). I shed light on how and under which conditions quantum sampling devices can be tested or verified in regimes that are not simulable on classical computers (Part II). Finally, I explore the computational boundary between classical and quantum computing devices (Part III). In particular, I develop efficiently computable measures of the infamous Monte Carlo sign problem and assess those measures both in terms of their practicability as a tool for alleviating or easing the sign problem and the computational complexity of this task. \u0000An overarching theme of the thesis is the quantum sign problem which arises due to destructive interference between paths -- an intrinsically quantum effect. The (non-)existence of a sign problem takes on the role as a criterion which delineates the boundary between classical and quantum computing devices. I begin the thesis by identifying the quantum sign problem as a root of the computational intractability of quantum output probabilities. It turns out that the intricate structure of the probability distributions the sign problem gives rise to, prohibits their verification from few samples. In an ironic twist, I show that assessing the intrinsic sign problem of a quantum system is again an intractable problem.","PeriodicalId":8484,"journal":{"name":"arXiv: Quantum Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80803030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Random matrix theory of the isospectral twirling 等谱旋转的随机矩阵理论

arXiv: Quantum Physics Pub Date : 2020-12-14 DOI: 10.21468/SCIPOSTPHYS.10.3.076

Salvatore F. E. Oliviero, L. Leone, F. Caravelli, A. Hamma

引用次数: 17

Self-testing of binary Pauli measurements requiring neither entanglement nor any dimensional restriction 二泡利测量的自我测试，既不需要纠缠也不需要任何尺寸限制

arXiv: Quantum Physics Pub Date : 2020-12-14 DOI: 10.1103/PhysRevA.103.062604

Ananda G. Maity, S. Mal, C. Jebarathinam, A. S. Majumdar

引用次数: 7

Optical spin control and coherence properties of acceptor bound holes in strained GaAs 应变砷化镓中受体结合孔的光学自旋控制和相干特性

arXiv: Quantum Physics Pub Date : 2020-12-13 DOI: 10.1103/PHYSREVB.103.115412

X. Linpeng, T. Karin, M. Durnev, M. Glazov, R. Schott, A. Wieck, A. Ludwig, K. Fu

引用次数: 2

Quantum supremacy and quantum phase transitions 量子霸权和量子相变

arXiv: Quantum Physics Pub Date : 2020-12-11 DOI: 10.1103/PHYSREVB.103.165132

Supanut Thanasilp, J. Tangpanitanon, M. Lemonde, Ninnat Dangniam, D. Angelakis

{"title":"Quantum supremacy and quantum phase transitions","authors":"Supanut Thanasilp, J. Tangpanitanon, M. Lemonde, Ninnat Dangniam, D. Angelakis","doi":"10.1103/PHYSREVB.103.165132","DOIUrl":"https://doi.org/10.1103/PHYSREVB.103.165132","url":null,"abstract":"Demonstrating the ability of existing quantum platforms to perform certain computational tasks intractable to classical computers represents a cornerstone in quantum computing. Despite the growing number of such proposed \"quantum supreme\" tasks, it remains an important challenge to identify their direct applications. In this work, we describe how the approach proposed in Ref. [arXiv:2002.11946] for demonstrating quantum supremacy in generic driven analog many-body systems, such as those found in cold atom and ion setups, can be extended to explore dynamical quantum phase transitions. We show how key quantum supremacy signatures, such as the distance between the output distribution and the expected Porter Thomas distribution at the supremacy regime, can be used as effective order parameters. We apply this approach to a periodically driven disordered 1D Ising model and show that we can accurately capture the transition between the driven thermalized and many-body localized phases. This approach also captures the transition towards the Floquet prethermalized regime for high-frequency driving. Revisiting quantum phases of matter under the light of the recent discussions about quantum supremacy draws a link between complexity theory and analog many-body systems.","PeriodicalId":8484,"journal":{"name":"arXiv: Quantum Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79198124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4