One-Way Quantum Computer Simulation
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Quantum Entanglement Concentration Based on Nonlinear Optics for Quantum Communications
Entropy 2013, 15, 1776-1820; doi:10.3390/e15051776 OPEN ACCESS entropy ISSN 1099-4300 www.mdpi.com/journal/entropy Review Quantum Entanglement Concentration Based on Nonlinear Optics for Quantum Communications Yu-Bo Sheng 1;2;* and Lan Zhou 2;3 1 Institute of Signal Processing Transmission, Nanjing University of Posts and Telecommunications, Nanjing 210003, China 2 Key Lab of Broadband Wireless Communication and Sensor Network Technology, Nanjing University of Posts and Telecommunications, Ministry of Education, Nanjing 210003, China 3 College of Mathematics & Physics, Nanjing University of Posts and Telecommunications, Nanjing 210003, China; E-Mail: [email protected] (L.Z.) * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel./Fax: +86-025-83492417. Received: 14 March 2013; in revised form: 3 May 2013 / Accepted: 8 May 2013 / Published: 16 May 2013 Abstract: Entanglement concentration is of most importance in long distance quantum communication and quantum computation. It is to distill maximally entangled states from pure partially entangled states based on the local operation and classical communication. In this review, we will mainly describe two kinds of entanglement concentration protocols. One is to concentrate the partially entangled Bell-state, and the other is to concentrate the partially entangled W state. Some protocols are feasible in current experimental conditions and suitable for the optical, electric and quantum-dot and optical microcavity systems. Keywords: quantum entanglement; entanglement concentration; quantum communication 1. Introduction Quantum communication and quantum computation have attracted much attention over the last 20 years, due to the absolute safety in the information transmission for quantum communication and the super fast factoring for quantum computation [1,2]. -
Quantum Macroscopicity Versus Distillation of Macroscopic
Quantum macroscopicity versus distillation of macroscopic superpositions Benjamin Yadin1 and Vlatko Vedral1, 2 1Atomic and Laser Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK 2Centre for Quantum Technologies, National University of Singapore, Singapore 117543 (Dated: October 7, 2018) We suggest a way to quantify a type of macroscopic entanglement via distillation of Greenberger- Horne-Zeilinger states by local operations and classical communication. We analyze how this relates to an existing measure of quantum macroscopicity based on the quantum Fisher information in sev- eral examples. Both cluster states and Kitaev surface code states are found to not be macroscopically quantum but can be distilled into macroscopic superpositions. We look at these distillation pro- tocols in more detail and ask whether they are robust to perturbations. One key result is that one-dimensional cluster states are not distilled robustly but higher-dimensional cluster states are. PACS numbers: 03.65.Ta, 03.67.Mn, 03.65.Ud I. INTRODUCTION noted here by N ∗. We will not impose any cut-off above which a value of N ∗ counts as macroscopic, but instead Despite the overwhelming successes of quantum me- consider families of states parameterized by some obvious chanics, one of its greatest remaining problems is to ex- size quantity N (e.g. the number of qubits). Then the plain why it appears to break down at the macroscopic relevant property of the family is the scaling of N ∗ with scale. In particular, macroscopic objects are never seen N. The case N ∗ = O(N) is ‘maximally macroscopic’ [9]. in quantum superpositions. -
Bidirectional Quantum Controlled Teleportation by Using Five-Qubit Entangled State As a Quantum Channel
Bidirectional Quantum Controlled Teleportation by Using Five-qubit Entangled State as a Quantum Channel Moein Sarvaghad-Moghaddam1,*, Ahmed Farouk2, Hussein Abulkasim3 to each other simultaneously. Unfortunately, the proposed Abstract— In this paper, a novel protocol is proposed for protocol required additional quantum and classical resources so implementing BQCT by using five-qubit entangled states as a that the users required two-qubit measurements and applying quantum channel which in the same time, the communicated users global unitary operations. There are many approaches and can teleport each one-qubit state to each other under permission prototypes for the exploitation of quantum principles to secure of controller. The proposed protocol depends on the Controlled- the communication between two parties and multi-parties [18, NOT operation, proper single-qubit unitary operations and single- 19, 20, 21, 22]. While these approaches used different qubit measurement in the Z-basis and X-basis. The results showed that the protocol is more efficient from the perspective such as techniques for achieving a private communication among lower shared qubits and, single qubit measurements compared to authorized users, but most of them depend on the generation of the previous work. Furthermore, the probability of obtaining secret random keys [23, 2]. In this paper, a novel protocol is Charlie’s qubit by eavesdropper is reduced, and supervisor can proposed for implementing BQCT by using five-qubit control one of the users or every two users. Also, we present a new entanglement state as a quantum channel. In this protocol, users method for transmitting n and m-qubits entangled states between may transmit an unknown one-qubit quantum state to each other Alice and Bob using proposed protocol. -
Graphical and Programming Support for Simulations of Quantum Computations
AGH University of Science and Technology in Kraków Faculty of Computer Science, Electronics and Telecommunications Institute of Computer Science Master of Science Thesis Graphical and programming support for simulations of quantum computations Joanna Patrzyk Supervisor: dr inż. Katarzyna Rycerz Kraków 2014 OŚWIADCZENIE AUTORA PRACY Oświadczam, świadoma odpowiedzialności karnej za poświadczenie nieprawdy, że niniejszą pracę dyplomową wykonałam osobiście i samodzielnie, i nie korzystałam ze źródeł innych niż wymienione w pracy. ................................... PODPIS Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie Wydział Informatyki, Elektroniki i Telekomunikacji Katedra Informatyki Praca Magisterska Graficzne i programowe wsparcie dla symulacji obliczeń kwantowych Joanna Patrzyk Opiekun: dr inż. Katarzyna Rycerz Kraków 2014 Acknowledgements I would like to express my sincere gratitude to my supervisor, Dr Katarzyna Rycerz, for the continuous support of my M.Sc. study, for her patience, motivation, enthusiasm, and immense knowledge. Her guidance helped me a lot during my research and writing of this thesis. I would also like to thank Dr Marian Bubak, for his suggestions and valuable advices, and for provision of the materials used in this study. I would also thank Dr Włodzimierz Funika and Dr Maciej Malawski for their support and constructive remarks concerning the QuIDE simulator. My special thank goes to Bartłomiej Patrzyk for the encouragement, suggestions, ideas and a great support during this study. Abstract The field of Quantum Computing is recently rapidly developing. However before it transits from the theory into practical solutions, there is a need for simulating the quantum computations, in order to analyze them and investigate their possible applications. Today, there are many software tools which simulate quantum computers. -
G53NSC and G54NSC Non Standard Computation Research Presentations
G53NSC and G54NSC Non Standard Computation Research Presentations March the 23rd and 30th, 2010 Tuesday the 23rd of March, 2010 11:00 - James Barratt • Quantum error correction 11:30 - Adam Christopher Dunkley and Domanic Nathan Curtis Smith- • Jones One-Way quantum computation and the Measurement calculus 12:00 - Jack Ewing and Dean Bowler • Physical realisations of quantum computers Tuesday the 30th of March, 2010 11:00 - Jiri Kremser and Ondrej Bozek Quantum cellular automaton • 11:30 - Andrew Paul Sharkey and Richard Stokes Entropy and Infor- • mation 12:00 - Daniel Nicholas Kiss Quantum cryptography • 1 QUANTUM ERROR CORRECTION JAMES BARRATT Abstract. Quantum error correction is currently considered to be an extremely impor- tant area of quantum computing as any physically realisable quantum computer will need to contend with the issues of decoherence and other quantum noise. A number of tech- niques have been developed that provide some protection against these problems, which will be discussed. 1. Introduction It has been realised that the quantum mechanical behaviour of matter at the atomic and subatomic scale may be used to speed up certain computations. This is mainly due to the fact that according to the laws of quantum mechanics particles can exist in a superposition of classical states. A single bit of information can be modelled in a number of ways by particles at this scale. This leads to the notion of a qubit (quantum bit), which is the quantum analogue of a classical bit, that can exist in the states 0, 1 or a superposition of the two. A number of quantum algorithms have been invented that provide considerable improvement on their best known classical counterparts, providing the impetus to build a quantum computer. -
Quadratic Entanglement Criteria for Qutrits K
Vol. 137 (2020) ACTA PHYSICA POLONICA A No. 3 Quadratic Entanglement Criteria for Qutrits K. Rosołeka, M. Wieśniaka;b;∗and L. Knipsc;d aInstitute of Theoretical Physics and Astrophysics, Faculty of Mathematics, Physics, and Informatics, University of Gdańsk, 80-308 Gdańsk, Poland bInternational Centre for Theories of Quantum Technologies, University of Gdańsk, Wita Swosza 57, 80-308 Gdańsk, Poland cMax-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching, Germany dDepartment für Physik, Ludwig-Maximilians-Universität, D-80797 München, Germany (Received September 10, 2019; revised version December 2, 2019; in final form December 5, 2019) The problem of detecting non-classical correlations of states of many qudits is incomparably more involved than in the case of qubits. One reason is that for qubits we have a convenient description of the system by the means of the well-studied correlation tensor allowing to encode the complete information about the state in mean values of dichotomic measurements. The other reason is the more complicated structure of the state space, where, for example, different Schmidt ranks or bound entanglement comes into play. We demonstrate that for three-dimensional quantum subsystems we are able to formulate nonlinear entanglement criteria of the state with existing formalisms. We also point out where the idea for constructing these criteria fails for higher-dimensional systems, which poses well-defined open questions. DOI: 10.12693/APhysPolA.137.374 PACS/topics: quantum information, quantum correlations, entanglements, qutrits 1. Introduction practical reasons. The task is very simple for pure states, which practically never occur in a real life. However, for For complex quantum systems, we distinguish between mixed states, it is still an open question. -
QUANTUM COMPUTER and QUANTUM ALGORITHM for TRAVELLING SALESMAN PROBLEM Utpal Roy, Sanchita Pal Chawdhury, Susmita Nayek
ISSN: 0974-3308, VOL. 2, NO. 1, JUNE 2009 © SRIMCA 54 QUANTUM COMPUTER AND QUANTUM ALGORITHM FOR TRAVELLING SALESMAN PROBLEM Utpal Roy, Sanchita Pal Chawdhury, Susmita Nayek ABSTRACT Depending upon the extraordinary power of Quantum Computing Algorithms various branches like Quantum Cryptography, Quantum Information Technology, Quantum Teleportation have emerged [1-4]. It is thought that this power of Quantum Computing Algorithms can also be successfully applied to many combinatorial optimization problems. In this article, a class of combinatorial optimization problem is chosen as case study under Quantum Computing. These problems are widely believed to be unsolvable in polynomial time. Mostly it provides suboptimal solutions in finite time using best known classical algorithms. Travelling Salesman Problem (TSP) is one such problem to be studied here. A great deal of effort has already been devoted towards devising efficient algorithms that can solve the problem [5-18]. Moreover, the methods of finding solutions for the TSP with Artificial Neural Network and Genetic Algorithms [5-8] do not provide the exact solution to the problems for all the cases, excepting a few. A successful attempt has been made to have a deterministic solution for TSP by applying the power of Quantum Computing Algorithm. Keywords: Quantum Computing, Travelling Salesman Problem, Quantum algorithms. 1. INTRODUCTION A quantum computer is a device that can arbitrarily manipulate the quantum state of a part or itself. The field of quantum computation is largely a body of theoretical promises for some impressively fast algorithms which could be executed on quantum computers. The field of quantum computing has advanced remarkably in the past few years since Shor [1] presented his quantum mechanical algorithm for efficient prime factorization of very large numbers, potentially providing an exponential speedup over the fastness on known classical algorithm. -
Download the 3Rd Edition of the Book of Abstracts
Book of Abstracts 3rd BSC International Doctoral Symposium Editors Nia Alexandrov María José García Miraz Graphic and Cover Design: Cristian Opi Muro Laura Bermúdez Guerrero This is an open access book registered at UPC Commons (http://upcommons.upc.edu) under a Creative Commons license to protect its contents and increase its visibility. This book is available at http://www.bsc.es/doctoral-symposium-2016 published by: Barcelona Supercomputing Center supported by: The “Severo Ochoa Centres of Excellence" programme 3rd Edition, September 2016 Introduction ACKNOWLEDGEMENTS The BSC Education & Training team gratefully acknowledges all the PhD candidates, Postdoc researchers, experts and especially the Keynote Speaker Francisco J. Doblas-Reyes and the tutorial lecturers Vassil Alexandrov and Javier Espinosa, for contributing to this Book of Abstracts and participating in the 3rd BSC International Doctoral Symposium 2016. We also wish to expressly thank the volunteers that supported the organisation of the event: Carles Riera and Felipe Nathan De Oliveira. BSC Education & Training team [email protected] 5 Introduction 6 Introduction CONTENTS EDITORIAL COMMENT ................................................................................................ 11 WELCOME ADDRESS .................................................................................................. 13 PROGRAM .................................................................................................................... 15 KEYNOTE SPEAKER ................................................................................................... -
Models of Quantum Computation and Quantum Programming Languages
Models of quantum computation and quantum programming languages Jaros law Adam MISZCZAK Institute of Theoretical and Applied Informatics, Polish Academy of Sciences, Ba ltycka 5, 44-100 Gliwice, Poland The goal of the presented paper is to provide an introduction to the basic computational mod- els used in quantum information theory. We review various models of quantum Turing machine, quantum circuits and quantum random access machine (QRAM) along with their classical counter- parts. We also provide an introduction to quantum programming languages, which are developed using the QRAM model. We review the syntax of several existing quantum programming languages and discuss their features and limitations. I. INTRODUCTION of existing models of quantum computation is biased towards the models interesting for the development of Computational process must be studied using the fixed quantum programming languages. Thus we neglect some model of computational device. This paper introduces models which are not directly related to this area (e.g. the basic models of computation used in quantum in- quantum automata or topological quantum computa- formation theory. We show how these models are defined tion). by extending classical models. We start by introducing some basic facts about clas- A. Quantum information theory sical and quantum Turing machines. These models help to understand how useful quantum computing can be. It can be also used to discuss the difference between Quantum information theory is a new, fascinating field quantum and classical computation. For the sake of com- of research which aims to use quantum mechanical de- pleteness we also give a brief introduction to the main res- scription of the system to perform computational tasks. -
Quantum Computing Cluster State Model
Quantum Computing Cluster State Model Phillip Blakey, Alex Karapetyan, Thomas Ma December 2019 1 Introduction The traditional circuit-based model of quantum computation is strictly based on unitary evolution. Especially in view of the Principle of Deferred Measurement in the context of implementation of algorithms with the circuit model, the role of measurement is secondary to unitary quantum gates - a quantum circuit, sans the final measurements, is the application of a carefully crafted unitary transformation to a carefully chosen initial quantum state. Measurement is a non-unitary operation and thereby ruins quantum states. The cluster state model of quantum computing, also known as a \one-way quantum computer", is based on the idea of performing a sequence of single-qubit measurements on some large initial state, resulting in an output in the form of a several-qubit state. In particular, measurement is essential to the entirety of any computation, in contrast to the circuit model. This model was first introduced in [1] (see also [2]), and it has been studied from both the theoretical and experimental implementation points of view. The initial state of a computation in this model, called a cluster state, is a specially prepared entangled state associated to a particularly chosen graph. To perform a quantum computation on a cluster state, the rules of the game are: (a) the allowed operations are single-qubit measurements in any basis on any of the nodes of the graph, (b) the basis in which to measure at every stage of the sequence is conditioned on the outcome of the previous measurement, and (c) efficient classical processing is allowed on the measurement outcomes. -
Logical Measurement-Based Quantum Computation in Circuit-QED
www.nature.com/scientificreports OPEN Logical measurement-based quantum computation in circuit- QED Jaewoo Joo1,2*, Chang-Woo Lee 1,3, Shingo Kono4 & Jaewan Kim1 We propose a new scheme of measurement-based quantum computation (MBQC) using an error- correcting code against photon-loss in circuit quantum electrodynamics. We describe a specifc protocol of logical single-qubit gates given by sequential cavity measurements for logical MBQC and a generalised Schrödinger cat state is used for a continuous-variable (CV) logical qubit captured in a microwave cavity. To apply an error-correcting scheme on the logical qubit, we utilise a d-dimensional quantum system called a qudit. It is assumed that a three CV-qudit entangled state is initially prepared in three jointed cavities and the microwave qudit states are individually controlled, operated, and measured through a readout resonator coupled with an ancillary superconducting qubit. We then examine a practical approach of how to create the CV-qudit cluster state via a cross-Kerr interaction induced by intermediary superconducting qubits between neighbouring cavities under the Jaynes- Cummings Hamiltonian. This approach could be scalable for building 2D logical cluster states and therefore will pave a new pathway of logical MBQC in superconducting circuits toward fault-tolerant quantum computing. Measurement-based quantum computation (MBQC) ofers a new platform of quantum information (QI) pro- cessing. Quantum algorithms are performed by sequential single-qubit measurements in multipartite entangled states initially (e.g., cluster states1) instead of massive controls of individual qubits during the whole information processing2,3. Tis advantage is, however, only benefcial for QI processing if the specifc multipartite entangled state can be initially well-prepared and the capability of fast and precise single-qubit measurements are viable. -
Large-Scale Cluster-State Entanglement in the Quantum Optical Frequency Comb
Large-Scale Cluster-State Entanglement in the Quantum Optical Frequency Comb Moran Chen Nanchong, Sichuan, China B.S. Physics, Beijing Normal University, 2009 A Dissertation presented to the Graduate Faculty of the University of Virginia in Candidacy for the degree of Doctor of Philosophy Department of Physics University of Virginia May 2015 c Copyright All Rights Reserved Moran Chen Ph.D., May 2015 i Acknowledgments First of all, I would like to thank my adviser, Prof. Olivier Pfister. Without his help and guidance, all of the research and work described in this thesis would have been impossible. I am wholeheartedly grateful to have him as my adviser. He gave me enough freedom and trust to allow me to conduct research and independent thinking on my own, and his incredible patience and knowledge in both the theory and in the experiments also gave me confidence and reassurance when I came across obstacles and difficulties. He is also always encouraging and kind, and is the best adviser I could have hoped for. He has led me into the amazing field of quantum optics, and I am truly blessed to have him as my adviser. I want to give special thanks to our theoretical collaborator Nick Menicucci. Nick is an outstanding theorist and a very smart, quick and straightforward person, and it has always been a pleasure talking with him about research topics or other general issues. We had many good and interesting discussions and his genius ideas and simplified theoretical proposals helped make our experiment easier and more feasible. I am truly thankful to have him as our theoretical collaborator and friend.