Freiburg 2024 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 24: Poster II
Q 24.8: Poster
Dienstag, 12. März 2024, 17:00–19:00, KG I Foyer
Anomalous non-thermal fixed point in a quasi-2d dipolar Bose gas — •Niklas Rasch1, Santo Maria Roccuzzo1,2, Wyatt Kirkby1,2, Lauriane Chomaz2, and Thomas Gasenzer1,3 — 1Kirchhoff-Institut für Physik, Universität Heidelberg, Im Neuenheimer Feld 227 — 2Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226 — 3Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16
In this work we focus on anomalous non-thermal fixed-points in the temporal evolution of a 2d dipolar Bose gas, exhibiting slow, subdiffusive coarsening characterized by algebraic growth of a characteristic length scale L(t)∼ tβ with β≪1/2. Starting from variously sampled vortices on a uniform background, we evolve the Bose gas using the semi-classical truncated-Wigner approach. In the classical regime we reproduce the anomalous scaling exponent β≃1/5 known from the single-component Bose gas with contact interactions, for various dipolar strengths and tilting angles. In the quantum regime we also recover such anomalously slow, subdiffusive scaling but find a dependence on the tilting angle, which leads to different scaling exponents and less stable scaling regimes. Within a quasi-2d setting, we analyze the dependence of the observed scaling exponents on the effects of anisotropy and on the long-range nature of the dipolar interaction. Anisotropy in the vortex configuration emerges; however, it is not reflected in the self-similar scaling. We focus on the role of vortex (anti-)clustering and observe regimes of strong clustering without correlation with the emergence of anomalously slow scaling.
Keywords: Non-Thermal Fixed Points; Dipolar gases; non-equilibrium; scaling; vortices