Physics

Prof. Luis Santos
Institute of Theoretical Physics,Germany

Abstract :

I will discuss two different scenarios where the physics of dipolar gases may differ qualitatively from that of non-dipolar ones. In the first part I will focus on dipolar Bose-Einstein condensates, and in particular on dipolar quantum droplets and dipolar rotons, two phenomena of particular interest due to recent breakthrough experiments. I will discuss dipolar rotons in elongated traps, which have been recently observed in Innsbruck experiments [1]. Concerning quantum droplets I will comment on the analogies and differences between dipolar condensates and binary Bose mixtures, and comment on 1D dipolar condensates where a peculiar 1D-to-3D crossover of the character of quantum fluctuations may be observed [2]. In the second part of the talk, I will consider a rather different system: polar molecules pinned at random positions in an optical lattice, in which pseudo-spin rotational excitations propagate via dipolar flip-flops. I will show that these molecules realize a peculiar single-particle disorder model with 1/r³ hops, characterized by multi-fractal non-ergodic eigenstates [3]. If I have time, I will discuss our more recent work on general power-law hops [4] in 1D systems, where localization is found even for long-range hops. Moreover, long- and short-range hops present a remarkable duality in their localization properties.

[1] L. Chomaz, R. M. W. van Bijnen, D. Petter, G. Faraoni, S. Baier, J. H. Becher, M. J. Mark, F. Wächtler, L. Santos, and F. Ferlaino, Nature Physics 2018.

[2] D. Edler, C. Mishra, F. Wächtler, R. Nath, S. Sinha, and L. Santos, Phys. Rev. Lett. 119, 050403 (2017).

[3] X. Deng, B.L. Altshuler, G.V. Shlyapnikov, and L. Santos, Phys. Rev. Lett. 117, 020401 (2016).

[4] X. Deng, V. E. Kravtsov, G. V. Shlyapnikov, L. Santos, Phys. Rev. Lett., in press 2018.