Preprints

    1 a 4 de 4 Preprints encontradas Ano: 2017

  • GOIQ - UFRJ
    GOQIQ - UFMG
    GMCT - UFRJ
    Photonic Counterparts of Cooper Pairs
    André Saraiva, Filomeno S. de Aguiar Júnior, Reinaldo de Melo e Souza, Arthur Patrocínio Pena, Carlos H. Monken, Marcelo F. Santos, Belita Koiller, Ado Jorio
    Phys. Rev. Lett. 119, 193603 (2017)
    ArXiv: https://arxiv.org/abs/1709.04520
    Abstract

    The microscopic theory of superconductivity raised the disruptive idea that electrons couple through the elusive exchange of virtual phonons, overcoming the strong Coulomb repulsion to form Cooper pairs. Light is also known to interact with atomic vibrations, as, for example, in the Raman effect. We show that photon pairs exchange virtual vibrations in transparent media, leading to an effective photon-photon interaction identical to that for electrons in the BCS theory of superconductivity, in spite of the fact that photons are bosons. In this scenario, photons may exchange energy without matching a quantum of vibration of the medium. As a result, pair correlations for photons scattered away from the Raman resonances are expected to be enhanced. An experimental demonstration of this effect is provided here by time-correlated Raman measurements in different media. The experimental data confirm our theoretical interpretation of a photonic Cooper pairing, without the need for any fitting parameters.

  • GOIQ - UFRJ
    Unified framework to determine Gaussian states in continuous-variable systems
    Fernando Nicacio, Andrea Valdés-Hernández, Ana P. Majtey, Fabricio Toscano
    Phys. Rev. A 96, 042341 (2017)
    ArXiv: https://arxiv.org/pdf/1707.01966.pdf
  • GOQIQ - UFMG
    GOIQ - UFRJ
    Coarse graining a non-Markovian collisional model
    Nadja K. Bernardes, Andre R. R. Carvalho, C. H. Monken, Marcelo F. Santos
    Phys. Rev. A 95, 032117 (2017)
    ArXiv: https://arxiv.org/abs/1701.06419
  • GIQ-UFABC
    GCQIQ - CBPF
    Reversing the thermodynamic arrow of time using quantum correlations
    Kaonan Micadei, John P. S. Peterson, Alexandre M. Souza, Roberto S. Sarthour, Ivan S. Oliveira, Gabriel T. Landi, Tiago B. Batalhão, Roberto M. Serra, Eric Lutz
    arXiv:1711.03323 (2017)
    ArXiv: https://arxiv.org/abs/1711.03323
    Abstract

    The second law permits the prediction of the direction of natural processes, thus defining a thermodynamic arrow of time. However, standard thermodynamics presupposes the absence of initial correlations between interacting systems. We here experimentally demonstrate the reversal of the arrow of time for two initially quantum correlated spins-1/2, prepared in local thermal states at different temperatures, employing a Nuclear Magnetic Resonance setup. We observe a spontaneous heat flow from the cold to the hot system. This process is enabled by a trade off between correlations and entropy that we quantify with information-theoretical quantities.

Ano

LIMPAR FILTRO

GRUPOS