Qutrit State Engineering with Biphotons

Bogdanov, Yu. I.; Chekhova, Maria V.; Kulik, S. P.; Maslennikov, Gleb; Жуков, А. А.; Oh, C. H.; Tey, Meng Khoon

doi:10.1103/physrevlett.93.230503

Cited by 138 publications

(113 citation statements)

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“…Experimental demonstration-We encode the information on polarizations of photon pairs [23][24][25][26] generated by the spontaneous four-wave-mixing in a piece of optical fiber [27][28][29], by which the 3-dimensional system for the test of I 3 and the 4-dimensional system for the tests of I 4 and R 4 are realized. The setup is shown in FIG.3.…”

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confidence: 99%

Experimental device-independent tests of classical and quantum entropy

et al. 2016

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In this paper, we report an experiment about the device-independent tests of classical and quantum entropy based on a recent proposal [Phys. Rev. Lett. 115, 110501 (2015)], in which the states are encoded on the polarization of a biphoton system and measured by the state tomography technology. We also theoretically obtained the minimal quantum entropy for three widely used linear dimension witnesses. The experimental results agree well with the theoretical analysis, demonstrating that lower entropy is needed in quantum systems than that in classical systems under given values of the dimension witness. Introduction-The device-independent quantum information processing is attractive and developing rapidly. Since the imperfection of practical devices will reduce the security of the quantum key distribution, the device-independent quantum key distribution was proposed against the collective attacks from the eavesdroppers [1]. It is independent of the internal working of the devices used in the implementation. The security is guaranteed from the observed data without any reference on the states and measurements.

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Section: Figmentioning

confidence: 99%

Experimental device-independent tests of classical and quantum entropy

et al. 2016

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“…Our approach can be used on a variety of photon states such as those created by combining nonorthogonal photon modes [16], those that combine the output from different spontaneous parametric downconversion sources [11] and those generated by stimulated parametric downconversion [17]. Although this paper treats systems of two photons, the same technique can be readily extended to a larger number of photons.…”

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“…The effect results in photons with the same characteristics entering the same mode, making it impossible to individually address the photons, i.e., to manipulate or measure them individually. Many other major results in the field of quantum optics such as the generation of Bell states, the demonstration of teleportation [6], linear optics quantum computing [7], the generation of cluster states [8] and the demonstration of quantum logic gates[9, 10] also use nonclassical interference and necessarily involve states with indistinguishable, non-individually-addressable photons.Numerous experiments have directly studied the properties of non-individually-addressable photons [11,12,13]. The work of Bogdanov et al showed that the polarization state of two photons forms a controllable three-level system or qutrit suitable for many protocols in quantum information [3] and quantum cryptography [14,15] and proposes a method for performing state tomography to characterize the density matrix of the qutrit state.…”

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confidence: 99%

“…Numerous experiments have directly studied the properties of non-individually-addressable photons [11,12,13]. The work of Bogdanov et al showed that the polarization state of two photons forms a controllable three-level system or qutrit suitable for many protocols in quantum information [3] and quantum cryptography [14,15] and proposes a method for performing state tomography to characterize the density matrix of the qutrit state.…”

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confidence: 99%

“…If one starts from the assumption that the photons are indistinguishable in the hidden degrees of freedom as in [11] then one will use a 3 × 3 matrix to describe a polarization qutrit as opposed to the 4 × 4 matrix used for distinguishable photons [19]. For a more general description one could allow for a distinguishing degree of freedom and explore what limitations the fact that it is hidden places on measuring density matrix elements.…”

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Multiparticle State Tomography: Hidden Differences

et al. 2007

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We address the problem of completely characterizing multi-particle states including loss of information to unobserved degrees of freedom. In systems where non-classical interference plays a role, such as linear-optics quantum gates, such information can degrade interference in two ways, by decoherence and by distinguishing the particles. Distinguishing information, often the limiting factor for quantum optical devices, is not correctly described by previous state-reconstruction techniques, which account only for decoherence. We extend these techniques and find that a single modified density matrix can completely describe partially-coherent, partially-distinguishable states. We use this observation to experimentally characterize two-photon polarization states in single-mode optical fiber.PACS numbers: 03.65. Wj,05.30.Jp,42.50.St The development of techniques for characterizing pure and mixed quantum states has enabled many advances in quantum information and related fields. Whether in order to study the effects of decoherence [1], to optimize the performance of quantum logic gates [2], to quantify the amount of information obtainable by various parties in quantum communications protocols [3], or to adapt quantum error correction protocols to real-world situations [4], it is first necessary to obtain as complete a characterization as possible of the state of a given quantum system (or ensemble). In the general case of mixed states, this involves reconstruction of a density matrix, a mathematically complete description of the degrees of freedom of interest in a quantum system. Entanglement with experimentally inaccessible or 'hidden' degrees of freedom (sometimes called "the environment") enters the density matrix as a reduction in the off-diagonal coherences. In some quantum systems -those composed of multiple particles that cannot be individually addressed -reduced coherence can only partially describe the effects of hidden degrees of freedom. Another phenomenon, distinguishability, arises when hidden degrees of freedom provide information that could in principle be used to tell the particles apart without necessarily leading to any changes in the coherences of the density matrix. This paper will show how a density matrix characterization of such states can be performed while taking into account the decoherence and distinguishability as distinct phenomena.Systems of particles that cannot be individually addressed occur commonly in quantum optics and elsewhere. A central example is the Hong-Ou-Mandel (HOM) effect [5], in which non-classical interference causes photon bunching at a beamsplitter. The effect results in photons with the same characteristics entering the same mode, making it impossible to individually address the photons, i.e., to manipulate or measure them individually. Many other major results in the field of quantum optics such as the generation of Bell states, the demonstration of teleportation [6], linear optics quantum computing [7], the generation of cluster states [8] and the demonstration o...

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