Dissertations / Theses on the topic 'Teleportation'
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Linn, Andreas. "Gaze Teleportation in Virtual Reality." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-216585.
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This paper reports preliminary investigations into gaze teleportation, a locomotion interaction inside virtual reality in which the user can push a button and teleport to the point at which they are looking. The results could help future application creators design intuitive locomotion interfaces to allow users to more easily scale virtual worlds larger than their play space. In a study consisting of 12 participants, gaze teleportation was compared to the conventional hand-tracked controller. Participants played a portion of Valve’s The Lab with an HTC Vive and a Tobii Eyetracker; half of the participants completed the set tasks with gaze teleportation, and the other half used hand-tracking. Using Likert questions, they then rated their experiences in terms of enjoyment, frustration, effort, distance, occlusion, immersion, and motion sickness. After answering the questions, the participants got to try both methods and were interviewed on their preferences and opinions. Our results suggest that gaze teleportation is an enjoyable, fast, intuitive, and natural locomotion method that performs similarly to hand-tracked teleportation but is preferred by users when they are given a choice. We conclude that gaze teleportation is a good fit for applications in which users are expected to locomote in their direction of focus without too many distractions.I det här dokumentet rapporteras preliminära resultat av blickteleportation, en rörelseinteraktion för virtuella verkligheter där användaren kan trycka på en knapp och teleportera till den punkt som de tittar på. Resultaten kan hjälpa framtida applikationsskapare att designa intuitiva rörelsegränssnitt så att användarna lättare kan röra sig i virtuella världar som är större än deras spelrum. I en studie med 12 deltagare jämfördes blick med teleportation med den konventionella handkontroll metoden. Deltagarna spelade en del av Valve’s The Lab med en HTC Vive och en Tobii Eyetracker; Hälften av deltagarna slutförde de uppsatta uppgifterna med blickteleportation, och den andra hälften använde handmetoden. Med Likert-frågor bedömde de sedan sina erfarenheter när det gällde njutning, frustration, ansträngning, avstånd, ocklusion och rörelsesjuka. Efter att ha besvarat frågorna fick deltagarna prova båda metoderna och intervjuades om sina preferenser och åsikter. Våra resultat tyder på att blickteleportation är en trevlig, snabb, intuitiv och naturlig rörelseinteraktion som presterar likt handmetoden, men föredras av användarna när de får välja. Vi drar slutsatsen att blickteleportation passar bra för applikationer där användarna förväntas förflytta sig i samma riktning som deras fokus.
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at, Andreas Cap@esi ac. "Designing Optimum CP Maps for Quantum Teleportation." ESI preprints, 2001. ftp://ftp.esi.ac.at/pub/Preprints/esi1080.ps.
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Dolinska, Aska. "The investigation of quantum polarisation teleportation protocol." View electronic text, 2002. http://eprints.anu.edu.au/documents/disk0/00/00/07/87/index.html.
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Thesis (BSc. (Hons))--Australian National University, 2002.Available via the Australian National University Library Electronic Pre and Post Print Repository. Title from title screen (viewed Mar. 28, 2003). "A thesis submitted for the degree of Bachelor of Science in Physics, The Australian National University" Bibliography: p. 77-80.
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Clark, Sean. "Measurement-based quantum computation and teleportation groups." Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443708.
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Kreft, Heinz [Verfasser]. "fairCASH based on Loss resistant Teleportation / Heinz Kreft." Aachen : Shaker, 2011. http://d-nb.info/1074087801/34.
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Mariano, Antonio Lorenzo. "Entanglement and teleportation in chains of graphene quantum dots." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13524/.
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The main characteristic of good standard teleportation protocol is to provide maximum fidelity better than the classical one. We find that a system of electrons in a chain of graphene quantum dots can ensure this requirement. Starting from the characterization of the bound states in quantum dots, based on ribbons of graphene with armchair boundaries, we derive the effective Hamiltonian that describes an open chain of spin-1/2 particles. We propose a configuration by which the nearest-neighbours dimerized interactions along the chain can ensure long distance entanglement between the outer sites. Through numerical results we highlight the trend of the entanglement and the maximum fidelity with respect to the parameters describing the graphene quantum dots chain.
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Avveduti, Silvia. "Analysis of multi-hop Teleportation Protocols for Quantum Networks." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/19934/.
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Quantum mechanics for computation and information purposes has seen a burst of interest in the scientific community and companies, due to the potential unique computational power offered by quantum computers, not achievable through classical computers. In particular two technologies are used in most quantum computers, which are the trapped ions and artificial atoms, but many different technologies are currently being studied for the physical implementation of quantum information systems. Quantum computers are challenging to build, because the element which represents information, the qubit, requires strict conditions such as isolation from the environment and a very refined control. Moreover, qubits cannot intrinsically reject noise as classical bits do. This thesis is organized as follows. In Chapter 2 the essential concepts for Quantum Computation and Information are introduced; in Chapter 3 an overview of the main applications is displayed; in Chapter 4 the current results in entanglement and teleportation in Quantum Network protocols are shown. The experimental outcomes obtained in IBM Q are discussed in Chapter 5. Finally, Chapter 6 contains the conclusions.
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Albotǎ, Marius A. 1974. "Single-photon frequency upconversion for long-distance quantum teleportation and communication." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37899.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 133-139).
Entanglement generation, single-photon detection, and frequency translation that preserves the polarization quantum state of the photons are essential technologies for long distance quantum communication protocols. This thesis investigates the application of polarization entanglement to quantum communication, including frequency upconversion, photon-counting detection, and photon-pair and entanglement generation. We demonstrate a near-unity efficient frequency conversion scheme that allows fast and efficient photon counting at wavelengths in the low-loss fiber optic and atmospheric transmission band near 1.55 /im. This upconverter, which is polarization-selective, is useful for classical as well as quantum optical communication. We investigate several schemes that allow frequency translation of polarization-entangled photons generated via spontaneous parametric downconversion in second order non-linear crystals. We demonstrate upconversion from 1.56 to 0.633 m that preserves the polarization state of an arbitrarily polarized input. The polarization-insensitive upconverter uses bidirectional sum-frequency generation in bulk periodically poled lithium niobate and a Michelson interferometer to stabilize the phase. Using this bidirectional upconversion technique, entangled photons produced in a periodically poled parametric downconverter can be translated to a different wavelength with preservation of their polarization state. We discuss the implications of these results for quantum information processing.
by Marius A. Albota.
Ph.D.
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Mendes, Fernando Vasconcelos. "Quantum gate teleportation, universal entanglers and connections with the number theory." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13647.
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The present thesis can be divided in three parts: 1) Quantum gate teleportation; 2) Numerical search of universal entanglers; 3) Connections between quantum information and number theory. Regarding the quantum gate teleportation, a separability criterion of normal matrices is used to find the analytical conditions of the preservation of separability under conjugation. That analytical condition allowed to find the general formula of an element of $mathbb{C}^{4}$ Clifford group, as well to understand the
role of the basis of measurement in the quantum gate teleportation protocol. Considering the searching for universal entanglers, the same separability criterion of normal matrices was used as fitness function in a computational heuristics, in prder to find good candidates for universal entanglers in $mathbb{C}^{3} otimes mathbb{C}^{4}$ and $mathbb{C}^{4} otimes mathbb{C}^{4}$ Hilbert spaces. At last, in the connection of quantum information with the number theory, it is presented the study of the preparation and entanglement of several multi-qubit quantum states based in integer sequences, and the Riemannian quantum circuit, a quantum circuit whose eigenvalues are related to the zeros of the Riemann zeta function. The existence of such circuit proves that is always possible to construct a physical system related to a finite amount of zeros.A presente tese està dividida em trÃs partes: 1) TeleportaÃÃo de portas quÃnticas; 2) Busca numÃrica por entrelaÃadores universais; 3) ConexÃes entre a informaÃÃo quÃntica e a teoria dos nÃmeros. No que diz a teleportaÃÃo de portas quÃnticas, um critÃrio de separabilidade para matrizes normais à usada para encontrar as condiÃÃes analÃticas da preservaÃÃo da separabilidade sob conjugaÃÃo. Tais condiÃÃes analÃticas permitiram encontrar a forma geral de um elemento do grupo de Clifford em $mathbb{C}^{4}$, assim como tambÃm entender o papel da base de mediÃÃo no protocolo de teleportaÃÃo de portas quÃnticas. Considerando a busca por entrelaÃadores universais, o mesmo critÃrio de separabilidade de matrizes normais foi utilizado como funÃÃo de aptidÃo em uma heurÃstica computacional aplicada para encontrar bons candidatos a entrelaÃadores universais nos espaÃos de Hilbert de dimensÃes $mathbb{C}^{3} otimes mathbb{C}^{4}$ e $mathbb{C}^{4} otimes mathbb{C}^{4}$. Por fim, sobre as conexÃes da informaÃÃo quÃntica com a teoria dos nÃmeros, à apresentado um estudo da preparaÃÃo e entrelaÃamento de vÃrios estados quÃnticos de mÃltiplos qubits baseados em sequÃncias de nÃmeros inteiros. Apresenta-se ainda o circuito quÃntico Riemanniano, um circuito quÃntico cujos autovalores sÃo relacionados aos zeros da funÃÃo Zeta de Riemann. A existÃncia deste circuito prova que à sempre possÃvel construir um sistema fÃsico relacionado a uma quantidade finita de zeros.
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Aung, Joe 1978. "Quantum error modelling and correction in long distance teleportation using singlet states." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87202.
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Strelchuk, Sergii. "Superactivation of the channel capacity and teleportation protocols in quantum information theory." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648259.
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Di, Tiegang. "Entanglement generation and applications in quantum information." Texas A&M University, 2006. http://hdl.handle.net/1969.1/3840.
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This dissertation consists of three sections. In the first section, we discuss the generation
of arbitrary two-qubit entangled states and present three generation methods.
The first method is based on the interaction of an atom with classical and quantized
cavity fields. The second method is based on the interaction of two coupled two-level
atoms with a laser field. In the last method, we use two spin-1/2 systems which
interact with a tuned radio frequency pulse. Using those methods we have generated
two qubit arbitrary entangled states which is widely used in quantum computing and
quantum information. In the second section, we discuss a possible experimental implementation
of quantum walk which is based on the passage of an atom through a
high-Q cavity. The chirality is determined by the atomic states and the displacement
is characterized by the photon number inside the cavity. Our scheme makes quantum
walk possible in a cavity QED system and the results could be widely used on
quantum computer. In the last section, we investigate the properties of teleporting
an arbitrary superposition of entangled Dicke states of any number of atoms (qubits)
between two distant cavities. We also studied teleporting continuous variables of an
optical field. Teleportation of Dicke states relies on adiabatic passage using multiatom
dark states in each cavity and a conditional detection of photons leaking out of both cavities. In the continuous variables teleportation scheme we first reformulate
the protocol of quantum teleportation of arbitrary input optical field states in
the density matrix form, and established the relation between the P-function of the
input and output states. We then present a condition involving squeeze parameter
and detection efficiency under which the P-function of the output state becomes the
Q function of the input state such that any nonclassical features in the input state
will be eliminated in the teleported state. Based on the research in this section we
have made it possible of arbitrary atomic Dicke states teleportation from one cavity
to another, and this teleortation will play an essential role in quantum communication.
Since quantum properties is so important in quantum communication, the
condition we give in this section to distinguish classical and quantum teleportation is
also important.
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Henderson, L. "Quantum entanglement and classical information." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365802.
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Opanasiuk, Anatolii Serhiiovych, Анатолий Сергеевич Опанасюк, Анатолій Сергійович Опанасюк, and Р. І. Горовий. "Квантова телепортація." Thesis, Видавництво СумДУ, 2008. http://essuir.sumdu.edu.ua/handle/123456789/4189.
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Thorén, Alexander. "Quantum teleportation and its experimental realization : Teleporting moving quantum states onto a stationary medium." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-28204.
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A quantum mechanical state may be transferred between locations using quantum teleportation.Specically information encoded in the polarized state of a light pulse maybe teleported onto the collective spin state of an ensemble of atoms. This thesis providesa theoretical framework for achieving such a teleportation protocol experimentally.
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Sefi, Secgin [Verfasser], and Joachim von [Akademischer Betreuer] Zanthier. "Teleportation-based implementations of quantum optical continuous-variable gates / Secgin Sefi. Gutachter: Joachim von Zanthier." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2014. http://d-nb.info/107667383X/34.
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Ngobeni, Themba James. "Towards a framework for the implementation of a secure quantum teleportation infrastructure in South Africa." Thesis, Cape Peninsula University of Technology, 2019. http://hdl.handle.net/20.500.11838/3096.
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Thesis (MTech (Information Technology))--Cape Peninsula University of Technology, 2019The availability of high-speed/high-volume Data Link Layer (Layer 2) transmission networks fuelled by the implementation of mission critical and performance-intensive technologies, such as Cloud and Data Centre services transmitting sensitive data over the wide area network (WAN) has shifted the attention of hackers, eavesdroppers, cyber-criminals and other malicious attackers to the exploitation of these data transmission technologies. It is argued that security on the current classical technologies that store, transmit and manipulate information on the OSI Layer 2 have historically not been adequately addressed when it comes to secure communication and exchange of information. Quantum teleportation (QT) stemming from quantum communication a branch of quantum information science (QIS) has emerged as a technology that promise unconditional security and providing new ways to design and develop frameworks that operate based on the laws of quantum physics. It is argued that it has a potential to address the data transmission security GAP for OSI layer 2 technologies. This research study aims to propose a framework for the implementation of secure quantum teleportation infrastructures in South Africa. There is currently a lack of generic models and methods to guide the implementation of QT infrastructures that will enable secure transmission of information. A design science research (DSR) was undertaken in order to develop a secure quantum teleportation artefact called (SecureQT-Framework). SecureQT-Framework is a generic model and method that guides the selection and implementation of QT infrastructures motivated by multi-disciplinary domains such as QIS, Quantum Physics, Computer Science as well as information and communication technology (ICT). The DSR process employed a primary DSR cycle with four DSR sub-cycles which involved the awareness and suggestion phase guided by a systematic literature review (SLR), development and evaluation phase guided by Software Defined Network’s OpenFlow, Mininet, Mininet-Wifi and computer simulations for QT using SQUANCH framework. We investigated, examined and collected credible QT techniques and its variant protocols to develop and simulate secure transmission of information over the WAN, We studied their features and challenges. We concluded the study by describing the QT techniques, protocols and implementations that has potential to bridge the security GAP for OSI Layer 2 technologies over the WAN. The results gained were used in the construction of a framework for the implementation of a secure quantum teleportation infrastructure in South Africa. The framework describes the main factors that need to be taken into consideration when implementing quantum teleportation infrastructures.
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Рудченко, Д. Ю. "Квантовая телепортация." Thesis, Сумский государственный университет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/38848.
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В фантастической литературе и фильмах давно ввелось такое понятие, как телепортация, что считается невозможным, однако учёные постепенно приближаются к понимаю этого феномена.
Представьте, как бы телепортация упростила и облегчила нам жизнь. Не пришлось бы тратить время на переезды из одного города в другой, каждый желающий мог бы побывать на Луне или в какой-
нибудь другой части нашей солнечной системы или даже галактике. Но телепортация может использоваться и во вред человечеству – в войнах.
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Burchardt, Daniel [Verfasser], and Harald [Akademischer Betreuer] Weinfurter. "A rigorous test of Bell's inequality and quantum teleportation employing single atoms / Daniel Burchardt ; Betreuer: Harald Weinfurter." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2018. http://d-nb.info/1153712202/34.
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Djordjevic, Ivan B. "Integrated Optics Modules Based Proposal for Quantum Information Processing, Teleportation, QKD, and Quantum Error Correction Employing Photon Angular Momentum." IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2016. http://hdl.handle.net/10150/615122.
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To address key challenges for both quantum communication and quantum computing applications in a simultaneous manner, we propose to employ the photon angular momentum approach by invoking the well-known fact that photons carry both the spin angular momentum (SAM) and the orbital angular momentum (OAM). SAM is associated with polarization, while OAM is associated with azimuthal phase dependence of the complex electric field. Given that OAM eigenstates are mutually orthogonal, in principle, an arbitrary number of bits per single photon can be transmitted. The ability to generate/analyze states with different photon angular momentum, by using either holographic or interferometric methods, allows the realization of quantum states in multidimensional Hilbert space. Because OAM states provide an infinite basis state, while SAM states are 2-D only, the OAM can also be used to increase the security for quantum key distribution (QKD) applications and improve computational power for quantum computing applications. The goal of this paper is to describe photon angular momentum based deterministic universal quantum qudit gates, namely, {generalized-X, generalized-Z, generalized-CNOT} qudit gates, and different quantum modules of importance for various applications, including (fault-tolerant) quantum computing, teleportation, QKD, and quantum error correction. For instance, the basic quantum modules for quantum teleportation applications include the generalized-Bell-state generation module and the QFT-module. The basic quantum module for quantum error correction and fault-tolerant computing is the nonbinary syndrome calculator module. The basic module for entanglement assisted QKD is either the generalized-Bell-state generation module or the Weyl-operator-module. The possibility of implementing all these modules in integrated optics is discussed as well. Finally, we provide security analysis of entanglement assisted multidimensional QKD protocols, employing the proposed qudit modules, by taking into account the imperfect generation of OAM modes.
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Kruger, Markus Gustav. "On evolutionary algorithms for effective quantum computing." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20095.
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Thesis (MSc)--Stellenbosch University, 2012.ENGLISH ABSTRACT: The goal of this thesis is to present evolutionary algorithms, and demonstrate their applicability in quantum computing. As an introduction to evolutionary algorithms, it is applied to the simple but still challenging (from a computational viewpoint) Travelling Salesman Problem (TSP). This example is used to illustrate the e ect of various parameters like selection method, and maximum population size on the accuracy and e ciency of the evolutionary algorithms. For the sample problem, the 48 continental state capitals of the USA, solutions are evolved and compared to the known optimal solution. From this investigation tournament selection was shown to be the most e ective selection method, and that a population of 200 individuals per generation gave the most e ective convergence rates. In the next part of the thesis, evolutionary algorithms are applied to the generation of optimal quantum circuits for the following cases: The identity transformation : Picked for its simplicity as a test of the correct implementation of the evolutionary algorithm. The results of this investigation showed that the solver program functions correctly and that evolutionary algorithms can indeed nd valid solutions for this kind of problem. The work by Ding et al. [16] on optimal circuits for the two-qubit entanglement gate, controlled-S gate as well as the three qubit entanglement gate are solved by means of EA and the results compared. In all cases similar circuits are produced in fewer generations than the application of Ding et al. [16]. The three qubit quantum Fourier transform gate was also attempted, but no convergence was attained. The quantum teleportation algorithm is also investigated. Firstly the nature of the transformation that leads to quantum teleportation is considered. Next an e ective circuit is sought using evolutionary algorithms. The best result is one gate longer than Brassard [11], and seven gates longer than Yabuki [61].
AFRIKAANSE OPSOMMING: Die doel van hierdie tesis is om evolusionêre algoritmes te ondersoek en hulle toepaslikheid op kwantumkomputasie te demonstreer. As 'n inleiding tot evolusionêre algoritmes is die eenvoudige, maar steeds komputasioneel uitdagende handelsreisigerprobleem ondersoek. Die invloed van die keuse van 'n seleksie metode, sowel as die invloed van die maksimum aantal individue in 'n generasie op die akkuraatheid en e ektiwiteit van die algoritmes is ondersoek. As voorbeeld is die 48 kontinentale hoofstede van die state van die VSA gekies. Die oplossings wat met evolusionêre algoritmes verkry is, is met die bekende beste oplossings vergelyk. Die resultate van hierdie ondersoek was dat toernooi seleksie die mees e ektiewe seleksie metode is, en dat 200 individue per generasie die mees e ektiewe konvergensie tempo lewer. Evolusionêre algoritmes word vervolgens toegepas om optimale oplossings vir die volgende kwantumalgoritmes te genereer: Die identiteitstransformasie: Hierdie geval is gekies as 'n eenvoudige toepassing met 'n bekende oplossing. Die resultaat van hierdie toepassing van die program was dat dit korrek funksioneer, en vinnig by die korrekte oplossings uitkom. Vervolgens is daar ondersoek ingestel na vier van die gevalle wat in Ding et al. [16] bespreek word. Die spesi eke transformasies waarna gekyk is, is 'n optimale stroombaan vir twee kwabis verstrengeling, 'n beheerde-S hek, 'n drie kwabis verstrengelings hek, en 'n drie kwabis kwantum Fourier transform hek. In die eerste drie gevalle stem die oplossings ooreen met die van Ding et al. [16], en is die konvergensie tempo vinniger. Daar is geen oplossing vir die kwantum Fourier transform verkry nie. Laastens is daar na die kwantumteleportasiealgoritme gekyk. Die eerste stap was om te kyk na die transformasie wat in hierdie geval benodig word, en daarna is gepoog om 'n e ektiewe stroombaan te evolueer. Die beste resultaat was een hek langer as Brassard [11], en sewe hekke langer as Yabuki [61].
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Gray, Sean. "Quantum Entanglement and Cryptography." Thesis, Uppsala universitet, Teoretisk fysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-227085.
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In this paper the features of quantum systems which lay the foundation of quantum entanglement are studied. General properties of entangled states are discussed, including their entropy and relation to Bell's inequality. Applications of entanglement, namely quantum teleportation and quantum cryptography, are also considered.
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Konieczniak, Igor. "Teletransporte de informação quântica entre campos de cores distintas." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-14032019-094912/.
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Em 1993, Bennett propôs um protocolo de teletransporte de um estado quântico por meio de dois canais de comunicação de natureza distinta: Um canal clássico, formado por duas vias clássicas de informação, e um canal quântico, formado por um par de sistemas entrelaçados. Após algumas implementações bem-sucedidas no domínio de variáveis discretas, em 1998 surge uma versão de variáveis contínuas do protocolo [1]. No mesmo ano, Furusawa et al. realizam o teletransporte quântico incondicional baseado em variáveis contínuas do campo [2]. Recentemente, o emaranhamento no domínio de variáveis contínuas entre feixes intensos de luz com diferentes cores foi medido [3, 4, 5]. Neste trabalho relatamos os avanços na implementação do protocolo de teletransporte entre campos intensos de cores distintas. Depois de alguns esforços, conseguimos construir um oscilador paramétrico óptico (OPO) que se apresentou como uma fonte razoável de feixes intensos emaranhados. Os equipamentos necessários para a execução do protocolo foram construídos e instalados. Seguiram-se vários testes para garantir o funcionamento combinado de todas as partes. Entre eles, a teleportação de um estado de vácuo não deslocado, onde obtivemos resultados promissores. Após ajustes de configuração e desenvolvimento de técnicas de análise de dados para fornecer a produção, detecção e análise de estados deslocados do campo, o protocolo foi executado com esse tipo de estados. Alcançamos uma fidelidade de 45% para um estado de entrada deslocado, enquanto que a fidelidade considerando apenas as variâncias chegou a 60%. Para comprovar sucesso de nosso protocolo de teletransporte quântico, estão previstas algumas otimizações e alterações na operação do OPO, através das quais esperamos superar em breve a marca de 50% de fidelidade, correspondente ao limite clássico.In 1993, Bennett et al. [6] proposed a teleportation protocol of a quantum state by means of two communication channels of distinct natures: A classical channel, formed by two classical information pathways, and a quantum channel, formed by a pair of entangled systems. After some successful implementations in the discrete variables domain, in 1998 arises a continuous variables version of the teleportation protocol [1]. In the same year, Furusawa et al. accomplish the unconditional quantum teleportation based on continuous variables of the field. [2]. Recently, entanglement in the continuous variables domain between bright beams of light with different colors was measured [3, 4, 5]. In this work we report the advances on the teleportation protocol implementation between bright fields of distinct colors. After some struggle, we managed to build an Optical Parametric Oscillator (OPO) witch presented it self as a reasonable source of entangled bright beams. The setup required for the execution of the protocol was built and installed. This was followed by several tests to ensure the combined working of all parts. The teleportation of a nondisplaced vacuum state was one of the performed tests, on wich we achieved promising results. After setup adjustments and the developing of data analysis techniques to provide the production, detection and analysis of displaced states of the field, the protocol was run with this kind of states. We reached a fidelity of 45% for a displaced input state, while the fidelity considering only the variances was up to 60%. To prove the success of our quantum teleportation protocol, some optimizations and changes in the operation of the OPO are in plan, whereby we expect soon to surpass the 50% fidelity benchmark, corresponding to the classical limit.
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Konieczniak, Igor. "Teletransporte de informação quântica entre campos de cores distintas." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-29102014-161152/.
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Em 1993, Bennett et al. [1] postularam o processo de teletransporte de um estado quântico através do uso de dois canais de comunicação, um canal clássico e outro formado por um par de sistemas emaranhados. Na área de óptica quântica, várias realizações experimentais deste teletransporte foram relatadas [2, 3, 4], tanto no domínio de variáveis contínuas como discretas. Recentemente, foi medido emaranhamento no domínio de variáveis contínuas entre feixes de luz intensos de cores distintas [5, 6, 7]. Utilizando feixes com estas características como canal de comunicação quântico, apresentamos uma proposta para o primeiro teletransporte de informação quântica com troca de informação no domínio de variáveis contínuas entre campos de cores distintas. Resultados experimentais em direção à realização da proposta foram alcançados. Os moduladores eletro-ópticos, necessários na construção e reconstrução dos estados quânticos da luz, foram caracterizados. Quatro cavidades ópticas foram construídas, com requerido pelo protocolo para feixes de luz de cores distintas. Um oscilador paramétrico óptico (OPO) foi construído para a gerar os feixes correlacionados. No entanto, ele apresentou resultados insatisfatórios, atribuídos a um defeito no cristal não linear. Por isso, um OPO com novo cristal e novos espelhos foi projetado e se encontra em fase de construção. Por fim, um tratamento teórico adequado às particularidades da proposta experimental é apresentado.In 1993, Bennett et al. [1] postulated teleportation of quantum states by means of two communication channels, one classical and the other formed by a pair of entangled systems. In quantum optics, several experimental realizations of this teleportation process have been reported [2, 3, 4], both in the continuous and discrete variables domains. Recently, entanglement in the continuous variables domain between brigth beams of light with different colors were measured [5, 6, 7]. Using beams with these characteristics as a quantum comunication channel, we present a proposal for the first quantum information teleportation with exchange of information in the continuous variables domain between different color fields. Experimental results towards the proposal´s accomplishment have been achieved. The electro-optic modulators, needed in the preparation and reconstruction of quantum states of light, were characterized. Four optical cavities were built, as required by the protocol for multicolored light beams. An optical parametric oscillator (OPO) was built to generate the correlated beams. However, it showed unsatisfactory results, attributed to a defect in the nonlinear crystal. Therefore, an OPO with new crystal and new mirrors was designed and is under construction. Finally, a theoretical treatment appropriate to the particularities of the experimental proposal is presented.
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Тищенко, Д. В. "Телепортація." Thesis, Cумський державний університет, 2016. http://essuir.sumdu.edu.ua/handle/123456789/49067.
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Після створення надійних методів квантової телепортації виникнуть реальні передумови для створення квантових обчислювальних систем. Телепортація забезпечить надійну передачу та зберігання інформації на фоні потужних перешкод, коли всі інші способи виявляються неефективними, і можу бути використана для зв’язку між кількома квантовими комп’ютерами. Крім того, і самі розроблені дослідниками методи мають величезне значення для майбутніх експериментів з квантової механіки.
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Healey, Richard. "Quantum States as Objective Informational Bridges." Springer, 2015. http://hdl.handle.net/10150/623074.
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A quantum state represents neither properties of a physical system
nor anyone s knowledge of its properties. The important question is not
what quantum states represent but how they are used as informational
bridges. Knowing about some physical situations (its backing conditions),
an agent may assign a quantum state to form expectations about other
possible physical situations (its advice conditions). Quantum states are
objective: only expectations based on correct state assignments are gen-
erally reliable. If a quantum state represents anything, it is the objective
probabilistic relations between its backing conditions and its advice con-
ditions. This paper o¤ers an account of quantum states and their function
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Bastos, Wellison Peixoto. "Troca de Emaranhamento e Teletransporte Controlado no contexto de rotações de Faraday fotônicas." Universidade Federal de Goiás, 2011. http://repositorio.bc.ufg.br/tede/handle/tde/3027.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Taking advantage of the Faraday rotations that occur in a photonic cristal placed in an optical cavity with low quality factor, we proposed two schemes to obtain the swapping of entanglement of atomic states, useful in quantum communication and quantum computation. They employ three-level atoms in a -configuration, a linearly polarized photon source, a single detector, and a quarter wave plate. Three (four) cavities are used in the first (second) scheme. An additional scheme was also proposed to obtain controlled teleportation of superposition states, partial controlled teleportation of entangled states and controlled teleportation of entanglement. In all schemes we have included the imperfections that affect the system, such as transmission and coupling of photons in optical components, the fraction of photons with a desired polarization, the quantum efficiency of single photon detection, the effective solid angle where the photon are collected, and the rate of emitted photons by the source. Under these realistic conditions we estimate the success probability of each proccess, including the time spent for its realization.
Aproveitando as rotações de Faraday que ocorrem em um cristal fotônico colocado em uma cavidade óptica com baixo fator de qualidade, propusemos dois esquemas para obter a troca de emaranhamento de estados atômicos, útil em comunicação quântica e computação quântica. Eles empregam átomos de três níveis em uma configuração, uma fonte de fótons com polarização linear, um único detector, e uma placa de quarto de onda. Três (quatro) cavidades são usadas no primeiro (segundo) esquema. Um método adicional foi também proposto para obter teletransporte controlado de estados de superposição, teletransporte parcial controlado de estados emaranhados e teletransporte controlado de estados emaranhados. Em todos os esquemas incluímos as imperfeições que afetam o sistema, tais como a transmissão e acoplamento de fótons em componentes ópticos, a fração de fótons com uma polarização desejada, a eficiência quântica da detecção de um único fóton, o ângulo sólido efetivo em que o fótons são coletados e a taxa de fótons emitidos pela fonte. Sob estas condições realistas, estimamos a probabilidade de sucesso de cada processo, incluindo o tempo gasto para sua realização.
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Bergöö, Martin. "IDR "Interaktionsdesignad rädsla"." Thesis, Malmö högskola, Institutionen för konst, kultur och kommunikation (K3), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-23137.
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This essay focuses on the possibilities and problems that come with having teleportation mixed with horror and fear and not having monsters in fear games. How it is to play a horror game without enemies and just being able as an Interactiondesigner to relay on the psychological feeling within the player, if the feeling is more than enough if the player him self get to fantasies and let their deepest fright feelings take over. Is there no difference if there are monsters/enemies or not. Is fright and fear already there before you encountering the enemies? These questions are answered as the paper also presents a game in the shape of a course that has been paralleled worked with. The world with the complete and finished game have bin done in the Hammer editor which the game HalfLife2 (VU games/Valve Software, 2004) is built on. The finished game is a result of several user tests from the prototype game and user questionnaires. Fear games are mainly built on humans’ psychological feelings, the imaginations and how one feel. Through strong usage and building upon these main factors to create fear I have worked from that perspective and investigated how I by best possible means, should do to create fear to fright players by not using enemies as main frightening objects. Focus has been on the narrative of both visual and auditive narration. I have also given an account of the advantage and disadvantages with working with the tool I have chosen, how it has affected my work and my result. The Result turned out to be even better than I had in mind and a positive attitude towards my game from all the test persons. They thought it was a good example that a horror game is not bound to have monsters in order to fright the player. I got a loot of good feedback, response and ideas of what I could improve and what was already good. Some wanted more light effects on the first part and others less sound in the last part. By listening to the test persons I started to create and shape the final version of the game. Everyone became scared and felt more or less frightened through all four parts of the game. I also got positive feedback on my theory from the test persons, that teleportation mixed with horror and fear is something that they could consider using more in games and that this was a good start in the right direction.
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Metcalf, Benjamin James. "Silica-on-silicon waveguide circuits and superconducting detectors for integrated quantum information processing." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:8b5482f6-93a7-4d6e-b335-ba258ad3de1e.
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Building complex quantum systems has the potential to reveal phenomena that cannot be studied using classical simulation. Photonics has proven to be an effective test-bed for the investigation of such quantum-enhanced technologies, however, the proliferation of bulk optical components is unlikely to be a scalable route towards building more complex devices. Instead, the miniaturisation, inherent phase stability and trivial alignment afforded by integrated photonic systems has been shown to be a promising alternative. In the first half of this thesis, we describe experiments exploiting the quantum interference of three single photons on a reconfigurable integrated photonic chip. We develop a low-loss source of single photons and introduce a low-loss silica-on-silicon waveguide architecture which enables us to show the first genuine quantum interference of three single photons on an integrated platform. A loss-tolerant, element-wise characterisation scheme is developed along with a statistical test to verify that this multi-photon circuit behaves as expected. We then make use of this three-photon interference to detail the first proof-of-principle demonstration of a new intermediate model of quantum computation called boson sampling. Finally, we perform an on-chip demonstration of the quantum teleportation protocol where all key parts --- entanglement preparation, Bell-state analysis and quantum state tomography --- are performed on a reconfigurable photonic chip. The element-wise characterisation scheme developed earlier is shown to be critical to mitigate fabricated component errors. We develop a theoretical model to account for all sources of possible error in the circuit and find good agreement with the measured teleported state fidelities, which exceed the average teleportation fidelity possible with a classical device. We identify the elements of this error budget relevant to scaling and propose improvements to chip characterisation and fabrication in order to achieve high fidelity operation. In the second half, we discuss the use of high efficiency superconducting transition edge sensors in enabling quantum experiments using more photons. We detail the installation and characterisation of these detectors in a new lab in Oxford. We achieve good photon number-resolution and high-efficiency operation. Work to integrate these detectors on the silica-on-silicon waveguide architecture is discussed and we detail the optical and thermal device modelling performed to optimise the on-chip detection efficiency. New, on-chip detectors, fabricated according to this design are shown to operate as expected and achieve high-efficiency and good energy resolution.
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Medina, Ivan. "Uso de qubits ópticos no protocolo de teletransporte controlado." reponame:Repositório Institucional da UFABC, 2017.
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Orientador: Prof. Dr. Fernando Luis da Silva SemiãoDissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Física, 2017.
Começaremos esta dissertação introduzindo os conceitos básicos para a compreensão sobre informação quântica. Falaremos sobre qubits, operador densidade e sistemas compostos. Em seguida, discutiremos o uso de emaranhamento como recurso para a realização de protocolos quânticos e apresentaremos métodos para quantificá-lo. Como exemplos da utilidade de emaranhamento em tarefas de comunicação quântica, descreveremos os protocolos de teletransporte e de codificação superdensa. Prosseguiremos discutindo como as características de estados emaranhados levam ao fenômeno da não-localidade e como este fenômeno está relacionado com o protocolo de teletransporte. Em seguida, trataremos da quantização de um modo do campo eletromagnético e mostraremos que o hamiltoniano deste campo é formalmente igual ao de um oscilador harmônico de massa unitária. Discutiremos sobre as propriedades de dois tipos de estados relacionados a este modo do campo, os estados de Fock e os estados coerentes, e comentaremos como estes estados podem ser usados qubits. No último capítulo, apresentaremos o protocolo de teletransporte controlado. Como contribuição, iremos propor um modelo onde usamos qubits codificados em estados de Fock e estados coerentes para realização de tal protocolo. Levaremos em consideração perdas que ocorrem quando estes qubits são guiados através de fibras ópticas no modelo proposto. Introduziremos um parâmetro para quantificar a eficiência deste protocolo e iremos analisar como a performance do teletransporte é afetada pelas perdas na fibra para ambos os tipos de codificação. Para finalizar, estudaremos se existe alguma relação entre não-localidade genuinamente tripartida e a eficiência de teletransporte controlado.
This dissertation starts with an introduction on the basic concepts of quantum information. We then present the concepts of qubits, density operators and composite systems. This is followed by a discussion on how entanglement can be used as a resource for tasks in quantum information. Quantification methods for this resource are also presented. As examples of applications involving entanglement on quantum communication tasks, we describe the quantum teleportation and the superdense coding protocols. We finish this chapter with a discussion on how entanglement is related to the nonlocality phenomenon and how this is related to quantum teleportation. In the following chapter, we study the quantization of a single-mode electromagnetic field, and show that the hamiltonian of this field is formally equivalent to a unit-mass harmonic oscillator.We proceed to discuss the properties of two different types of states associated to the this field namely the Fock and coherent states, and comment on how they can be used to implement photonic qubits. In the last chapter, we present the controlled teleportation protocol. As a contribution, we propose a model where qubits based on either Fock or coherent states are used in that protocol. We take into account losses which occur when these qubits are guided through optical fibers. We introduce a parameter to quantify the efficiency of this protocol and analyze how its performance is affected for both types of encodings. Finally, we study whether or not a correlation between control teleportation efficiency and genuine tripartite nonlocality exists.
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Gomes, Raphael Fortes Infante. "Teletransporte quântico na presença de ruído." Universidade Federal de São Carlos, 2016. https://repositorio.ufscar.br/handle/ufscar/8143.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
The main focus of this work is to explore the feasibility of conducting the teleportation protocol in scenarios where the presence of an external environment reduces the purity of the input state and the transmission channel. To investigate the behavior of these protocols under realistic conditions, we selected the main decoherence maps reported in the literature concerning the description of this phenomenon, including the representation of mixed states through the Kraus operators and systems in thermal equilibrium whose Hamiltonian is described by the Heisenberg model. In this context, we proved that there are cases in which the in uence of external factors (such as increasing temperature and decoherence rates) and the immersion of those qubits in distinct environments help increasing the similarity between the properties of the original information and the teleported state. In addition, we studied the probabilistic teleportation protocol under the in uence of the same noise conditions analysed for the deterministic protocol, and the results here obtained show that the rst process can outperform the expected value of the average delity of the teleported state.
O foco do presente trabalho consiste em explorar a viabilidade de se realizar o teletransporte de estados quânticos arbitrários em cenários onde a presença de um ambiente externo reduz a pureza do estado de entrada e do canal de transmissão de informação. Para investigar o comportamento destes protocolos em condições realistas, selecionamos os principais mapas de de coerência registrados na literatura relativos à descrição deste fenômeno, incluindo a representação de estados mistos através dos operadores de Kraus e de sistemas em equilíbrio térmico cujo Hamiltoniano é descrito pelo modelo de Heisenberg. Neste contexto, provamos que existem casos nos quais a influência de fatores externos (como o aumento da temperatura e das taxas de de coerência) e a imersão de qubits em ambientes distintos contribui para aumentar a semelhança entre as propriedades da informação original e as do estado teletransportado. Além disso, estudamos o método de teletransporte probabilístico sob a influência dos mesmos tipos de ruídos analisados para o protocolo determinístico, e os resultados aqui apresentados demonstram que o primeiro processo é capaz de aumentar ainda mais o valor esperado da fidelidade média do estado teletransportado.
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Silka, Roman Ihorovych, Роман Игоревич Силка, and Роман Ігорович Сілка. "Парадокс Эйнштейна - Подольского - Розена. Квантовая телепортация." Thesis, Издательство СумГУ, 2008. http://essuir.sumdu.edu.ua/handle/123456789/4091.
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Научный руководитель: Игнатенко В.М.Парадокс Эйнштейна – Подольского – Розена является попыткой указания на неполноту квантовой механики с помощью мысленного эксперимента, заключающегося в измерении параметров микрообъекта косвенным образом, не оказывая на этот объект непосредственного воздействия. Согласно соотношению неопределённостей Гейзенберга, мы не можем измерить одновременно координату частицы и её импульс. Причина этого состоит в том, что производя измерение одной величины, мы вносим принципиально неустранимые возмущения в её движение и искажаем значение другой величины. Однако, можно предложить способ, с помощью которого соотношение неопределённостей можно обойти. При цитировании документа, используйте ссылку http://essuir.sumdu.edu.ua/handle/123456789/4091
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Mershin, Andreas. "Tubulin in vitro, in vivo and in silico." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/1635.
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Tubulin, microtubules and associated proteins were studied theoretically, computationally and experimentally in vitro and in vivo in order to elucidate the possible role these play in cellular information processing and storage. Use of the electric dipole moment of tubulin as the basis for binary switches (biobits) in nanofabricated circuits was explored with surface plasmon resonance, refractometry and dielectric spectroscopy. The effects of burdening the microtubular cytoskeleton of olfactory associative memory neurons with excess microtubule associated protein TAU in Drosophila fruitflies were determined. To investigate whether tubulin may be used as the substrate for quantum computation as a bioqubit, suggestions for experimental detection of quantum coherence and entanglement among tubulin electric dipole moment states were developed.
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Andrade, Rayssa Bruzaca de. "An optical parametric oscillator for a light- atomic media interface." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-18062018-052437/.
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In this work, we discuss a description of quantum properties of light beams produced by an Optical Parametric Oscillator (OPO) above threshold, pumped by a 780 nm Titanium Sapphire laser, resonant with the D2 line of Rb with a noise spectrum of a coherent beam. The twin beams have wavelengths around 1560nm, in the telecommunication band. The states emitted by the OPO under study are approximately Gaussian (1), which allows us to describe them in terms of first and second order moments. As we analyze the noise spectrum of the fluctuations of each beam, the first order moments are null, which allows us to describe the state of the system in terms of a covariance matrix. We present the behavior of the noise spectrum and the correlations between the reflected pump, signal and idler beams. In addition, we applied different entanglement criteria to study the system. We present a prediction of the bipartite entanglement using Duan criterion (2). For tripartite correlations, we use the Furusawa criterion (3). We performed a study of bipartition pump and sum quadrature. As well, we applied the PPT criterion (4) for continuous variables, independently transposing each beam under study. The PPT criterion is necessary and sufficient to demonstrate entanglement between bipartitions for Gaussian states. In order to explore the behavior of the system using the steering criterion in the model developed by Reid (5), we theoretically study the criterion of inference for bipartite quadratures: between the twin beams or between one of the twin beams and the pump beam. In addition, we analyzed the inference between the three modes, through the bipartition pump mode and combination of sum quadrature of the twin beams. We develop a quantum teleportation protocol of a coherent input state, composed by the Titanium Sapphire beam whose Bell measurement is performed using the pump reflected by the OPO as an entangled state for the signal and idler beams as a first possibility to implement the protocol. Furthermore, we propose a protocol in which the signal beam assists in the process of teleportation. Thus, the fidelity of the system increases and exceeds the limit of non-cloning. We will describe the first measurements of correlations between the beams emitted by the OPO for this system. The tripartite entanglement characterization is the first step in the implementation of quantum optical protocols using a source of entangled states that is compatible with both Rubidium atomic systems and the telecommunications region, thus forming a quantum network.Nesse trabalho apresentamos uma descrição das propriedades quânticas dos feixes de luz produzidos por um Oscilador Paramétrico Ótico (OPO) acima do limiar, bombeado por um laser de Titânio Safira com comprimento de onda de 780nm, linha D2 do Rb, com espectro de ruído de um feixe coerente. Os feixes gêmeos possuem comprimentos de onda na região de 1560 nm que compreende a janela de transmissão de fibras óticas. Os estados emitidos pelo OPO em estudo são aproximadamente gaussianos (1), o que nos permite descrevê-los em termos de momentos de primeira e segunda ordem. Como analisamos o espectro de ruído das flutuações de cada feixe, os momentos de primeira ordem são nulos, o que nos permite descrever o estado do sistema em termos de uma matriz de covariância. Apresentamos então o comportamento do espectro de ruído e das correlações entre os feixes de bombeio refletido, sinal e complementar. Ademais, aplicamos diferentes critérios de emaranhamento para estudar o sistema. Apresentamos uma previsão do emaranhamento bipartido utilizando o critério de Duan (2). Para as correlações tripartidas, utilizamos o critério de Furusawa (3). Realizamos um estudo da bipartição bombeio e quadratura soma. E, aplicamos o critério PPT para variáveis contínuas (4), transpondo independente cada feixe em estudo. O critério PPT é necessário e suficiente para demonstrar emaranhamento entre bipartições para estados gaussianos. Com o objetivo de explorar qual o comportamento do sistema frente ao critério de \"steering\" no modelo desenvolvido por Reid (5), estudamos teoricamente o critério de inferência para quadraturas bipartidas: entre os feixes gêmeos ou entre um dos feixes gêmeos e o feixe de bombeio. Finalizamos essa análise caracterizando a inferência entre os três modos, através da bipartição modo do bombeio e combinação das quadraturas soma dos feixes gêmeos. Apresentamos a formulação de um protocolo de teletransporte quântico de um estado coerente de entrada formado pelo feixe do Titânio Safira, cuja medida de Bell é realizada utilizando o bombeio refletido pelo OPO como estado emaranhado para os feixes sinal e complementar, como uma primeira possibilidade de implementar o protocolo. Também propomos um protocolo em que o feixe sinal auxilia no processo de teleportação. Dessa forma, a fidelidade do sistema aumenta e supera o limite da não clonagem. Descreveremos as primeiras medidas de correlações entre os feixes emitidos pelo OPO para esse sistema. A caracterização de emaranhamento tripartido nessa nova configuração é o primeiro passo para a implementação de protocolos de ótica quântica utilizando uma fonte de estados emaranhados que é compatível tanto com sistemas atômicos de Rubídio quanto com a região de telecomunicações, formando assim uma rede quântica de transferência e aprisionamento de informação.
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Gomes, Raphael Fortes Infante. "Estados parcialmente emaranhados em comunicação quântica." Universidade Federal de São Carlos, 2012. https://repositorio.ufscar.br/handle/ufscar/5039.
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Previous issue date: 2012-03-16Financiadora de Estudos e Projetos
In this master s thesis we approach the entanglement between quantum states as a resource to be used in the transmission of quantum information, particularly in quantum teleportation. Our focus was directed toward the study of partially entangled quantum states, that is, states in which the entanglement degree is below the maximum value allowed by quantum mechanics, since they are more likely to be found in actual devices than maximally entangled states. We review the properties and concepts that characterize vectors and operators from the viewpoint of linear algebra to formally present the postulates of quantum mechanics. We introduced the notion of qubits and showed how these can be applied to computing tasks via quantum logic gates.We explained in details the main quantum teleportation protocols that originated the methods used in this work, highlighting the advantages and disadvantages of each one. We presented protocols with new arrangements and introduced techniques that have improved some of the known methods, providing for those alternatives relating to construction and architecture in the arrangement of the channels. We proved that the probability associated with a multiple teleportation of a single qubit through channels in series tends to the maximum limit for a special case. We showed that imperfect states can be corrected and that it is possible to transmit a single qubit or a pair of qubits using GHZ states and modification of Bell basis states. We discussed the relationship between the final success probability value and the bases and channels degree of entanglement for each method. We concluded the thesis with a general analysis of all protocols, highlighting the most efficient ones with arguments that include theoretical and practical viewpoints.
Nesta dissertação abordamos o emaranhamento entre estados quânticos como um recurso a ser utilizado na transmissão de informação quântica, em especial no teletransporte quântico. Nosso foco foi direcionado para o estudo de estados quânticos parcialmente emaranhados, isto é, estados nos quais o teor de emaranhamento está aquém do máximo valor permitido pela mecânica quântica, visto que são mais prováveis de serem encontrados em dispositivos reais do que seriam estados maximamente emaranhados. Revisamos as propriedades e conceitos que caracterizam vetores e operadores sob a ótica da álgebra linear para em seguida apresentarmos formalmente os postulados da mecânica quântica. Introduzimos a noção de qubits e mostramos como estes podem ser aplicados em tarefas computacionais através de portas lógicas quânticas. Explicamos com detalhes os principais protocolos de teleporte quântico que originaram os métodos utilizados neste trabalho, destacando as vantagens e desvantagens de cada um. Apresentamos protocolos com arranjos inéditos e introduzimos técnicas que aperfeiçoaram alguns dos métodos de teleporte conhecidos, fornecendo alternativas para estes em relação à construção e arquitetura na disposição dos canais. Provamos que a probabilidade associada ao teleporte múltiplo de um qubit através de canais em série tende ao limite máximo para um caso especial. Mostramos que estados imperfeitos podem ser corrigidos e que é possível transmitir um qubit isolado ou um par de qubits empregando estados GHZ e modificações de estados da base de Bell. Discutimos a relação entre o valor da probabilidade de sucesso final e o grau de emaranhamento das bases e dos canais para cada método. Encerramos a dissertação com uma análise geral sobre todos os protocolos, destacando os mais eficientes com argumentos que englobam pontos de vista tanto teórico como prático.
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Dietz, Otto Verfasser], Oliver [Akademischer Betreuer] [Benson, Achim [Akademischer Betreuer] Peters, and Wolfram [Akademischer Betreuer] Pernice. "Linear and non-linear properties of light : Square Gradient Bragg scattering in dielectric waveguides (Part I) and two-color folded-sandwich entangled photon pair source for quantum teleportation (Part II) / Otto Dietz. Gutachter: Oliver Benson ; Achim Peters ; Wolfram Pernice." Berlin : Mathematisch-Naturwissenschaftliche Fakultät, 2016. http://d-nb.info/109733788X/34.
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Dietz, Otto [Verfasser], Oliver [Akademischer Betreuer] Benson, Achim [Akademischer Betreuer] Peters, and Wolfram [Akademischer Betreuer] Pernice. "Linear and non-linear properties of light : Square Gradient Bragg scattering in dielectric waveguides (Part I) and two-color folded-sandwich entangled photon pair source for quantum teleportation (Part II) / Otto Dietz. Gutachter: Oliver Benson ; Achim Peters ; Wolfram Pernice." Berlin : Mathematisch-Naturwissenschaftliche Fakultät, 2016. http://d-nb.info/109733788X/34.
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Lam, Ping Koy, and Ping Lam@anu edu au. "Applications of Quantum Electro-Optic Control and Squeezed Light." The Australian National University. Faculty of Science, 1999. http://thesis.anu.edu.au./public/adt-ANU20030611.170800.
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In this thesis, we report the observations of optical squeezing from second harmonic generation (SHG), optical parametric oscillation (OPO) and optical parametric amplification (OPA). Demonstrations and proposals of applications involving the squeezed light and electro-optic control loops are presented.
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In our SHG setup, we report the observation of 2.1 dB of intensity squeezing on the second harmonic (SH) output. Investigations into the system show that the squeezing performance of a SHG system is critically affected by the pump noise and a modular theory of noise propagation is developed to describe and quantify this effect. Our experimental data has also shown that in a low-loss SHG system, intra-cavity nondegenerate OPO modes can simultaneously occur. This competition of nonlinear processes leads to the optical clamping of the SH output power and in general can degrade the SH squeezing. We model this competition and show that it imposes a limit to the observable SH squeezing. Proposals for minimizing the effect of competition are presented.
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In our OPO setup, we report the observation of 7.1 dB of vacuum squeezing and more than 4 dB of intensity squeezing when the OPO is operating as a parametric amplifier. We present the design criteria and discuss the limits to the observable squeezing from the OPO.We attribute the large amount of squeezing obtained in our experiment to the high escape efficiency of the OPO. The effect of phase jitter on the squeezing of the vacuum state is modeled.
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The quantum noise performance of an electro-optic feedforward control loop is investigated. With classical coherent inputs, we demonstrate that vacuum fluctuations introduced at the beam splitter of the control loop can be completely cancelled by an optimum amount of positive feedforward. The cancellation of vacuum fluctuations leads to the possibility of noiseless signal amplification with the feedforward loop. Comparison shows that the feedforward amplifier is superior or at least comparable in performance with other noiseless amplification schemes. When combined with an injection-locked non-planar ring Nd:YAG laser, we demonstrate that signal and power amplifications can both be noiseless and independently variable.
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Using squeezed inputs to the feedforward control loop, we demonstrate that information carrying squeezed states can be made robust to large downstream transmission losses via a noiseless signal amplification. We show that the combination of a squeezed vacuum meter input and a feedforward loop is a quantum nondemolition (QND) device, with the feedforward loop providing an additional improvement on the transfer of signal. In general, the use of a squeezed vacuum meter input and an electro-optic feedforward loop can provide pre- and post- enhancements to many existing QND schemes.
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Finally, we proposed that the quantum teleportation of a continuous-wave optical state can be achieved using a pair of phase and amplitude electro-optic feedforward loops with two orthogonal quadrature squeezed inputs. The signal transfer and quantum correlation of the teleported optical state are analysed. We show that a two dimensional diagram, similar to the QND figures of merits, can be used to quantify the performance of a teleporter.
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Miller, Jamie M. "Personal Identity and the Extended Mind: A Critique of Parfitian Reductionism." Ohio University Honors Tutorial College / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1438280650.
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SOUZA, Alexandre Divino de. "Modelo de Jaynes-Cummings completo de dois fótons: estudo e aplicações." Universidade Federal de Goiás, 2009. http://repositorio.bc.ufg.br/tede/handle/tde/811.
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Previous issue date: 2009-02-20In this work we have studied the two photon Jaynes-Cummings model to describe the interaction of a three-level atom in the configuration with a single-mode of a cativy-field. We have used the effetive and full microscopic Jamiltonian approach to compare the results obtained in these tow descriptions. We employed the two-photon Jaynes-Cummings model int the full microscopic Hamiltonian context to implement schemes to quantuam entanglement swapping, for approximate and conditional quantuam teleportation for an unknown atomic state, for a superposition of zero- and two photon states. Both schemes were implemented using no measurement in the Bell base states.
Neste trabalho estudamos o modelo Jaynes-Cummings de dois fótons para descrever a interação de um átomo de Rydberg na configuração (ladeira) de três níveis com único modo do campo eletromagnético. A descrição deste sistema foi obtida usando o hamiltoniano efetivo e também o hamiltoniano microscópico completo, com o objetivo de compararmos resultados obtidos nas suas descrições. No modelo de Jaynes-Cummings de dois fótons descrito pleo hamiltoniano microscópico completo propusemos esquemas para realização de troca de emaranhamento quântico e teletransporte quântico aproximado e condicional de estados atômicos desconhecidos bem como estados de superposição de zeros e dois fótons do campo. Esses dois esquemas foram realizados sem uso de medida na base dos estados de Bell.
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Nilsson, Jonas. "Génération électrique de lumière intriquée destinée au transfert optique d'information quantique." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2013. http://tel.archives-ouvertes.fr/tel-00957826.
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Les boites quantiques de semiconducteurs représentent une voie attractive pour la réalisation de sources de photon efficaces pour le transfert quantique de l'information, avec un fort potentiel de miniaturisation et d'intégration. Dans ce travail, les paires de photons intriqués sont générées via le déclin radiatif de bi-excitons, à partir de boite quantiques d'InAs auto-assemblées placé dans une jonction p-i-n. Dans une première série d'expérience d'interférence à deux photons, nous avons démontré des corrélations de polarisation non classiques et la capacité de deux photons à interférer. L'intrication a été démontrée avec une fidélité de 0.87±0.04, et une visibilité des interférences de 0.60±0.05. Nous avons ensuite réalisé le premier téléporteur injecté électriquement dans un circuit à fibre monomode. Une fidélité moyenne de 0.704±0.016 a été mesurée pour 6 états distribués symétriquement sur la sphère de Poincaré, ce qui supérieur à la limite classique de 2/3 et prouve la téléportation. Un dispositif modifié de téléportation permettant d'injecter des photons à partir d'un laser continu indépendant a été développé. L'interférence à deux photons entre sources différentes a été démontrée et des battements quantiques observés. La téléportation quantique des états de polarisation portés par les photons a été obtenue avec une fidélité moyenne 0.76±0.012. Le contrôle du spin des charges confinés dans les nanostructures tels que les boites quantiques requiert une compréhension profonde de la physique des matériaux constituant, y compris au niveau nucléaire. Ainsi, nous avons démontré le contrôle électrique de l'interaction hyperfine entre les spins électroniques et nucléaires en utilisant un composant à charge ajustable. La modélisation suggère que le mécanisme est contrôlé par le temps de corrélation hyperfine de l'électron et le temps de dépolarisation du noyau.
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Cavaillès, Adrien. "Tests de non-localité et protocoles de communication quantique utilisant l'intrication hybride optique." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS055.
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Cette thèse est centrée sur la réalisation de protocoles d'information quantique utilisant conjointement les approches à variables discrètes et à variables continues de l'information quantique optique. Nous détaillons tout d'abord les protocoles utilisés pour la génération d'états hautement non classiques tels que les photons uniques, les chats de Schrödinger optiques et enfin l'intrication hybride entre variables discrètes et continues. Nous évaluons le potentiel de cette ressource innovante en détaillant son utilisation dans un certain nombre de protocoles. Nous commençons par envisager la réalisation de tests de Bell utilisant l'intrication hybride et rapportons l'observation expérimentale d'une violation d'inégalité de Steering, pour la première fois dans un contexte hybride. Enfin, nous détaillons l'état d'avancement de l'installation d'une nouvelle expérience de téléportation quantique entre variables discrètes et variables continues. Nos résultats prouvent l'intérêt de suivre une approche hybride et ouvrent la possibilité de réaliser des réseaux d'information quantique hybrides liant des systèmes de différentes naturesThere are two traditionally-separated approaches to optical quantum information: the continuous- and discrete-variable strategies respectively linked to the wave-like and particle-like nature of light. This thesis work is focused on the novel hybrid approach aiming to join the capabilities of both strategies into single systems. Using hybrid methods, we report on the use of optical parametric oscillators and superconducting-nanowire single-photon detectors to generate highly non-classical non-Gaussian states such as high-purity single-photons, Schr\"odinger cat states and finally hybrid entanglement of light between continuous- and discrete-variable encoding. The potential of this resource is studied in a number of protocols. We first consider non-locality tests with hybrid entanglement such as Bell inequality violation and experimentally demonstrate the violation of Einstein-Podolsky-Rosen steering inequalities. We finally report on the progress made towards the implementation of a new setup for the demonstration of hybrid quantum teleportation between continuous and discrete-variable encodings. Our demonstrations prove the versatility of this hybrid resource and open the possibility of implementing scalable quantum networks linking systems of dissimilar nature
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Felle, Martin Connor Patrick. "Telecom wavelength quantum devices." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/270019.
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Semiconductor quantum dots (QDs) are well established as sub-Poissonian sources of entangled photon pairs. To improve the utility of a QD light source, it would be advantageous to extend their emission further into the near infrared, into the low absorption wavelength windows utilised in long-haul optical telecommunication. Initial experiments succeeded in interfering O-band (1260—1360 nm) photons from an InAs/GaAs QD with dissimilar photons from a laser, an important mechanism for quantum teleportation. Interference visibilities as high as 60 ± 6 % were recorded, surpassing the 50 % threshold imposed by classical electrodynamics. Later, polarisation-entanglement of a similar QD was observed, with pairs of telecom-wavelength photons from the radiative cascade of the biexciton state exhibiting fidelities of 92.0 ± 0.2 % to the Bell state. Subsequently, an O-band telecom-wavelength quantum relay was realised. Again using an InAs/GaAs QD device, this represents the first implementation of a sub-Poissonian telecom-wavelength quantum relay, to the best knowledge of the author. The relay proved capable of implementing the famous four-state BB84 protocol, with a mean teleportation fidelity as high as 94.5 ± 2.2 %, which would contribute 0.385 secure bits per teleported qubit. After characterisation by way of quantum process tomography, the performance of the relay was also evaluated to be capable of implementing a six-state QKD protocol. In an effort to further extend the emitted light from a QD into the telecom C-band (1530—1565 nm), alternative material systems were investigated. InAs QDs on a substrate of InP were shown to emit much more readily in the fibre-telecom O- and C-bands than their InAs/GaAs counterparts, largely due to the reduced lattice mismatch between the QD and substrate for InAs/InP (~3 %) compared to InAs/GaAs (~7 %). Additionally, to minimize the fine structure splitting (FSS) of the exciton level, which deteriorates the observed polarisation-entanglement, a new mode of dot growth was investigated. Known as droplet epitaxy (D-E), QDs grown in this mode showed a fourfold reduction in the FSS compared to dots grown in the Stranski-Krastanow mode. This improvement would allow observation of polarisation-entanglement in the telecom C-band. In subsequent work performed by colleagues at the Toshiba Cambridge Research Labs, these D-E QDs were embedded in a p-i-n doped optical cavity, processed with electrical contacts, and found to emit entangled pairs of photons under electrical excitation. The work of this thesis provides considerable technological advances to the field of entangled-light sources, that in the near future may allow for deterministic quantum repeaters operating at megahertz rates, and in the further future could facilitate the distribution of coherent multipartite states across a distributed quantum network.
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Yen, Chia-Han, and 顏嘉漢. "Quantum Key Distribution with Teleportation." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/18768599768883527875.
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碩士國立清華大學
電機工程學系
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Quantum teleportation allows an unknown quantum state to be transmitted from one place to another with the aid of classical communication by first preparing an EPR pair for the sender and the receiver. We propose a novel quantum key distribution protocol based on this idea. This protocol does not require the sender and the receiver to choose between alternative measurements, which improves the rate of generating key bits from the transmitted bits and is hard for an eavesdropper to access information. However, our scheme needs reliable Bell operator measurements and the expensive resource, two Bell states each round. The security of our schemes discussed and compared with others.
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Chia-KuoChen and 陳嘉國. "Quantifying Quantum Teleportation and Its applications." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/35ch39.
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Jiang, Jin lin, and 江景霖. "Quantum identification scheme based on quantum teleportation." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/85205780439458269325.
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碩士南台科技大學
資訊工程系
93
1976, the public key cryptosystem based on one way function was proposed by Diffie and Hellman. Since then, there are many cryptosystems have been proposed such as RSA(based on factoring problem)、DSA (based on discrete logarithms problem) and ECC(based on elliptic curve discrete logarithms problem). Since 1994, Shor proposed quantum computing algorithms to solve factoring problem in polynomial time, quantum computing has become a hot subject for modern cryptography. Recently, many quantum identification schemes based on quantum mechanics or quantum computing algorithm are proposed. Therefore, we firstly review and study some famous quantum identification schemes and then analyze them from their theory, security advantages, and shortcomings. However, we find that many quantum cryptosystem about key distribute are assumed in noise-free quantum channel. In fact, this assumption is not reasonable; a quantum identification scheme based on quantum teleportation is proposed to overcome above problem in this paper.
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Jang, Yu-Ping, and 張鈺苹. "Tunneling Teleportation for Navigation in Virtual Environments." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/96cqz9.
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碩士國立臺灣大學
資訊網路與多媒體研究所
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The Virtual Reality (VR) sickness is a crucial issue when the users move in immersive virtual environments. The intense optical flow caused by virtual movements could make the users feel uncomfortable. Accordingly, many works and literature have worked on reducing the optical flow to alleviate the VR sickness. A lot of modern VR applications use blink teleportation [1] to hide the translation or a FOV restrictor [2] to decrease the users’ the optical flow of peripheral vision. However, blink translation can interrupt the users’ immersion, interference the spatial information gathering and lead to disorientation. On top of that, reducing the FOV will decrease spatial updating performance [3]. Therefore, we employ an additional spatial structure, a tunnel constructed by many portals, to retain users’ spatial awareness and offer a comfortable and immersive experience to the users. Three user studies are conducted for a well-designed tunnel used in our experimental virtual environment. In study 1, the thickness ratio parameter of each portal is adjusted to let users move comfortably. In study 2, we want to find the relationship between the brightness of the tunnel and the users’ preference, and the transparency of the tunnel is also adjusted to let users feel comfortable when moving in the tunnel. In the final study, we compare the tunneling teleportation with the blink teleportation based on the users’ comfort and the performance of the spatial orientation and the spatial information gathering. We suggest that VR developers can employ the tunneling teleportation to provide a comfortable and immersive experience.
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Jyun-YiLi and 李峻禕. "Hidden Teleportation Power For Entangled Quantum State." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/62cje4.
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碩士國立成功大學
物理學系
107
An ideal quantum teleportation transfers an unknown d-dimensional quantum state intact from one party to another via the use of a maximally entangled state. If Alice and Bob only share a classical resource, the teleportation fidelity, i.e., the maximal average fidelity between the state to be teleported and the state received is at most fc=2/(d+1), which corresponds to singlet fraction Fc=1/d. If they share an entangled state ρ with teleportation fidelity f〈fc (so equivalent to F〈Fc) and upon successful local filtering, the teleportation fidelity becomes larger than fc (or F〉Fc), we say that ρ has hidden teleportation power. Here, we investigate (1) the hidden teleportation power of a one-parameter family of entangled states and Werner state, (2) the trade-off between the success probability of local filtering and the extent to which the teleportation fidelity can be increased by this means,(3) the upper bound obtained by Rains’s semidefinite program [13], (4) difference between maximizing the singlet fraction after local filtering and maximizing cost function, (5) we also give an example of Mach-Zehnder interferometer to show how to measure the fidelity [5] of two photons in unknown states.
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Dolinska, Aska. "The investigation of quantum polarisation teleportation protocols." Thesis, 2002. http://hdl.handle.net/1885/41359.
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The continuous variables regime offers much promise for quantum information and computation protocols. In particular, the continuous variable polarisation teleportation is of great interest, both theoretically and experimentally, at the moment. In this thesis three schemes for continuous variable polarisation teleportation are analysed and their performance is rated. The double teleporter setup, the quantum nondemolition teleporter scheme and the biased entanglement teleporter setup are each discussed and evaluated. Two methods are employed for the evaluation of the teleportation success. The TV diagram which stresses the usefulness of the experimental design and the fidelity, which measures the quantum input to output state preservation. It is later shown that these two independent assessments, which consider physically different attributes, yield contradicting conclusions. Further it is shown that it is important to decide whether the objective of the polarisation teleportation is the transfer of information or the quantum state recreation before meaningful analysis using TV or fidelity can be made.
Finally, a study of a special cloning limit for a particular input state is made, related to the two of the above polarisation teleportation schemes. A new cloning fidelity limit is derived for these cases and TV cloning limits of information transfer and correlations are discussed.
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Jung-LunHsu and 許榮倫. "Quantum Teleportation and State Sharing Using Dicke State." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/54583002819943419837.
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