Preprints

    16 a 19 de 19 Preprints encontradas Ano: 2018

  • GOQIQ - UFMG
    GOIQ - UFRJ
    MathFoundQ - UNICAMP
    Noncontextual Wirings
    Barbara Amaral, Adán Cabello, Marcelo Terra Cunha, Leandro Aolita
    Phys. Rev. Lett. 120, 130403 (2018)
    ArXiv: kttps://arXiv.org/abs/1705.07911
  • GOIQ - UFRJ
    Relative phase shifts for metaplectic isotopies acting on mixed Gaussian states
    Maurice A. de Gosson, Fernando Nicacio
    Journal of Mathematical Physics 59 (2018)
    ArXiv: https://arxiv.org/abs/1802.07499
    Abstract

    We address in this paper the notion of relative phase shift for mixed quantum systems. We study the Pancharatnam-Sjoeqvist phase shift for metaplectic isotopies acting on Gaussian mixed states. We complete and generalize previous results obtained by one of us while giving rigorous proofs. This gives us the opportunity to review and complement the theory of the Conley-Zehnder index which plays an essential role in the determination of phase shifts.

  • GCQIQ - CBPF
    Quantum walks via quantum cellular automata
    Pedro C. S. Costa, Renato Portugal, Fernando de Melo
    Quantum Inf Process 17, 226 (2018)
    ArXiv: https://arxiv.org/abs/1803.02176
    Abstract

    Very much as its classical counterpart, quantum cellular automata are expected to be a great tool for simulating complex quantum systems. Here we introduce a partitioned model of quantum cellular automata and show how it can simulate, with the same amount of resources (in terms of effective Hilbert space dimension), various models of quantum walks. All the algorithms developed within quantum walk models are thus directly inherited by the quantum cellular automata. The latter, however, has its structure based on local interactions between qubits, and as such it can be more suitable for present (and future) experimental implementations.

  • GOIQ - UFRJ
    GOQIQ - UFMG
    Steady State Entanglement beyond Thermal Limits
    F. Tacchino, A. Auffèves, M. F. Santos, D. Gerace
    Phys. Rev. Lett. 120, 063604 (2018)
    ArXiv: https://arxiv.org/abs/1710.01377
    Abstract

    Classical engines turn thermal resources into work, which is maximized for reversible operations. The quantum realm has expanded the range of useful operations beyond energy conversion, and incoherent resources beyond thermal reservoirs. This is the case of entanglement generation in a driven-dissipative protocol, which we hereby analyze as a continuous quantum machine. We show that for such machines the more irreversible the process, the larger the concurrence. Maximal concurrence and entropy production are reached for the hot reservoir being at negative effective temperature, beating the limits set by classic thermal operations on an equivalent system.

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