1,356,268 research outputs found
High-fidelity Greenberger-Horne-Zeilinger state generation within nearby nodes
No full textGenerating entanglement in a distributed scenario is a fundamental task for implementing the quantum network of the future. We here report a protocol that uses only linear optics for generating Greenberger-Horne-Zeilinger states with high fidelities in a nearby node configuration. Moreover, we analytically show that the scheme is optimal for certain initial states in providing the highest success probability for sequential protocols. Finally, we give some estimates for the generation rate in a real scenario.QID/Wehner GroupQuantum Internet DivisionQuantum Information and Softwar
Experimental Greenberger–Horne–Zeilinger entanglement beyond qubits
No full textQuantum entanglement is important for emerging quantum technologies such as quantum computation and secure quantum networks. To boost these technologies, a race is currently ongoing to increase the number of particles in multiparticle entangled states, such as Greenberger–Horne–Zeilinger (GHZ) states. An alternative route is to increase the number of entangled quantum levels. Here, we overcome present experimental and technological challenges to create a three-particle GHZ state entangled in three levels for every particle. The resulting qutrit-entangled states are able to carry more information than entangled states of qubits. Our method, inspired by the computer algorithm Melvin, relies on a new multi-port that coherently manipulates several photons simultaneously in higher dimensions. The realization required us to develop a new high-brightness four-photon source entangled in orbital angular momentum. Our results allow qualitatively new refutations of local-realistic world views. We also expect that they will open up pathways for a further boost to quantum technologies
Experimental realization of dicke states of up to six qubits for multiparty quantum networking
No full textWe report the first experimental generation and characterization of a six-photon Dicke state. The produced state shows a fidelity of F=0.56±0.02 with respect to an ideal Dicke state and violates a witness detecting genuine six-qubit entanglement by 4 standard deviations. We confirm characteristic Dicke properties of our resource and demonstrate its versatility by projecting out four- and five-photon Dicke states, as well as four-photon Greenberger-Horne-Zeilinger and W states. We also show that Dicke states have interesting applications in multiparty quantum networking protocols such as open-destination teleportation, telecloning, and quantum secret sharing. © 2009 The American Physical Society
Nonlocality, violation of lorentz in variance, and wave-particle duality in quantum theory
No full textThis thesis addresses some of the consequences of giving quantum mechanics a realist interpretation. We consider three main topics: wave-particle duality, locality, and Lorentz invariance. First we show that classical particles alone or classical waves alone cannot explain all single particle quantum phenomena. Then we consider the possibility that a quantum particle is composed of a particle and a wave, both being taken to exist objectively. We are able to demonstrate the reality of empty waves (that is, waves without a particle) if we make three realist motivated assumptions. The main part of this thesis concerns locality. In 1964 Bell demonstrated that a local realist interpretation of quantum mechanics is not possible by deriving a set of inequalities that apply to two particle systems. More recently Greenberger, Home, and Zeilinger have demonstrated this for systems with more than two particles without the need for inequalities. We present a new way to derive Bell inequalities for two particles and show how this can be extended to systems with more than two particles. A number of proposals for experiments to test local realism are put forward. In particular, we show how it is possible to demonstrate the nonlocality of a single photon. A new demonstration of Bell's theorem is presented for two particles but without inequalities. A realizable quantum optical version is proposed and inequalities are proposed which would be required in a non-ideal experiment. Finally, the question of Lorentz invariance is considered. We define a condition for the existence of elements of reality and a condition for the Lorentz invariance of these elements of reality. Then we show that, by considering a particular gedanken experiment, we obtain a contradiction demonstrating that Lorentz-invariant realistic interpretations of quantum theory are not possible
Otto Zeilinger ex librise
No full texthttp://www.lib.unideb.huDebreceni Egyetem Egyetemi és Nemzeti KönyvtárA kép címerpajzsot formál, melynek alsó ívét két bőségszaru alkotja. Ezekből haszonnövények (gabona, tök, dinnye, káposzta) türemkednek ki. A pajzs felső részén kétoldalt két kisebb jelvény látható, a bal oldalin öt Dávid-csillag, a jobb oldalin két kard, görögkereszt, alatta két gömb látható. A bal oldali jelvényen arató figurája kaszával, korsóval,a jobb oldalin tiroli (stájer?) öltözetű vadász, vadászkutyával ül. A kompozíció középpontjában alpesi stílusú tanyaépület, melynek homlokzatán a kétfejű sas és az Otto Zeilinger felirat látható. Ex libris felirata: "Ex libris Otto Zeilinger 1920".metszetTheodor Martin
Responding to global challenges through data-driven art
No full textResearcher and curator Martin Zeilinger discusses a landscape review of AI art and artists in the context of responding to global challenges through data-driven art
Linear optical implementation of nonlocal product states and their indistinguishability
No full textIn a recent paper, Bennett et al. [Phys. Rev. A 59, 1070 (1999)] have shown the existence of a basis of product states of a bipartite system with manifest nonlocal properties. In particular these states cannot be completely discriminated by means of bilocal measurements. In this paper we propose an optical realization of these states and we will show that they cannot be completely discriminate by means of a global measurement using only optical linear elements, conditional transformation, and auxiliary photons
La physique quantique
No full textAnton Zeilinger, professeur à l’IQOQI (Institute for Quantum Optics and Quantum Information), et président de l’Académie des sciences d’Autriche a été invité par l’Assemblée des professeurs sur proposition de Serge Haroche et Jean Dalibard à donner deux conférences les 25 mars et 1er avril 2015 : “Quantum Imaging and the Role of Information”, “Quantum Entanglement in Higher Dimensions”. Anton Zeilinger Igor Dotsenko : Nombre de médias de vulgarisation scientifique tentent régulièrement de f..
Tensor-product states and local indistinguishability: An optical linear implementation
No full textIn this paper we investigate the properties of distinguishability of an orthogonal set of product states of two three level particle system by a simple class of joint measures. Here we confine ourselves to a system of analysis built up of linear elements, such as beam splitters and phase shifters, delay lines, electronically switched linear devices and auxiliary photons. We present here the impossibility of realization of a perfect never falling analyzer with this tools
Decomposition of the Brukner-Zeilinger invariant information with applications in wave-particle duality
No full textIn order to measure the inherent information content in a quantum state, Brukner and Zeilinger developed the idea of operationally invariant information in terms of the outcome probabilities of measuring a whole collection of mutually complementary observables. In this work, by partitioning the orthonormal operator basis of the associated operator Hilbert space into two complementary subsets, we establish a new decomposition of the Brukner-Zeilinger information. We further demonstrate that the two complementary components of the Brukner-Zeilinger information capture nicely the wave and particle features encoded in the quantum state after an n-path interferometer. Thus, we establish a universal complementarity relation involving the interference (wave feature) and the predictability (particle feature) via the unified concept of the Brukner-Zeilinger invariant information. These findings provide new characterizations of the wave-particle duality via the fundamental Brukner-Zeilinger invariant information
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