Interferences between Bogoliubov excitations and their impact on the evidence of superfluidity in a paraxial fluid of light
Quentin Fontaine, Pierre-Elie Larré, Giovanni Lerario, Tom Bienaimé, Simon Pigeon, Daniele Faccio, Iacopo Carusotto, Elisabeth Giacobino, Alberto Bramati, Quentin Glorieux
Paraxial fluids of light represent an alternative platform to atomic Bose-Einstein condensates and superfluid liquids for the study of the quantum behaviour of collective excitations. A key step in this direction is the precise characterization of the Bogoliubov dispersion relation, as recently shown in two experiments. However, the predicted interferences between the phonon excitations that would be a clear signature of the collective superfluid behaviour have not been observed to date. Here, by analytically, numerically, and experimentally exploring the phonon phase-velocity, we observe the presence of interferences between counter-propagating Bogoliubov excitations and demonstrate their critical impact on the measurement of the dispersion relation. These results are evidence of a key signature of light superfluidity and provide a novel characterization tool for quantum simulations with photons.
A century of the Bose-Einstein condensation concept and half a century of the JINR experiments for observation of condensate in the superfluid 4He (He II)
Institut de Mathématiques de Marseille - CNRS, Université d’Aix-Marseille（马赛数学研究所-法国国家科学研究中心，艾克斯-马赛大学）
Finite temperature effective field theory and two-band superfluidity in Fermi gases
我们发展了一个描述的费米子超流体的配对序参量的有效场论。我们的有效场论改进了现有的超流费米气体的Ginzburg-Landau理论，因为它不限于接近临界温度的温度。这是通过考虑所有订单的长期波动来实现的。本有效场论的结果与Bogoliubov - de Gennes方法的框架中得到的结果进行了比较。有效场论比Bogoliubov-de Gennes计算的优点是所需的计算时间少得多。在本文的第二部分中，我们将有效场论推广到双带超流体的情形。该理论揭示了双带超流体中两种愈合长度的存在，分析了BEC-BCS交叉中的有限温度涡旋结构，获得了集体激发的基态参数和谱.对于Leggett模式，我们的治疗提供了一个解释的观察，这种模式在两个波段的超导体。
Prethermalization in a quenched one-dimensional quantum fluid of light: Intrinsic limits to the coherent propagation of a light beam in a nonlinear optical fiber
Metastability, excitations, fluctuations, and multiple-swallowtail structures of a superfluid in a Bose-Einstein condensate in the presence of a uniformly moving defect
Université Paris-Saclay（巴黎萨克雷大学）；CNRS（法国国家科学研究中心）；LPTMS（理论与数学物理实验室）；Université Côte d’Azur（蔚蓝海岸大学）；INPHYNI（光与物质相互作用研究所）；Institut Universitaire de France (IUF)（法国高等研究院）；Laboratoire Kastler Brossel（卡斯特尔-布罗塞尔实验室）；Sorbonne Université（索邦大学）；ENS-PSL Research University（巴黎文理研究大学）；Collège de France（法兰西公学院）
