Bidirectional universal dynamics in a spinor Bose gas close to a nonthermal fixed point

• Verfasst von: Schmied, Christian-Marcel [VerfasserIn]
• Verfasst von: Prüfer, Maximilian [VerfasserIn]
• Verfasst von: Oberthaler, Markus K. [VerfasserIn]
• Verfasst von: Gasenzer, Thomas [VerfasserIn]
• Titel: Bidirectional universal dynamics in a spinor Bose gas close to a nonthermal fixed point
• Verf.angabe: Christian-Marcel Schmied, Maximilian Prüfer, Markus K. Oberthaler, and Thomas Gasenzer
• E-Jahr: 2019
• Jahr: 18 March 2019
• Umfang: 9 S.
• Fussnoten: Gesehen am 28.06.2019
• Titel Quelle: Enthalten in: Physical review
• Ort Quelle: Woodbury, NY : Inst., 2016
• Jahr Quelle: 2019
• Band/Heft Quelle: 99(2019,3) Artikel-Nummer 033611, 9 Seiten
• ISSN Quelle: 2469-9934
• DOI: doi:10.1103/PhysRevA.99.033611
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1668090287

Abstract

We numerically study the universal scaling dynamics of an isolated one-dimensional ferromagnetic spin-1 Bose gas. Preparing the system in a far-from-equilibrium initial state, simultaneous coarsening and refining is found to enable and characterize the approach to a nonthermal fixed point. A macroscopic length scale which scales in time according to LΛ(t)∼tβ, with β≃1/4, quantifies the coarsening of the size of spin textures. At the same time kinklike defects populating these textures undergo a refining process measured by a shrinking microscopic length scale Lλ∼tβ′, with β′≃−0.17. The combination of these scaling evolutions enables particle and energy conservation in the isolated system and constitutes a bidirectional transport in momentum space. The value of the coarsening exponent β suggests the dynamics to belong to the universality class of diffusive coarsening of the one-dimensional XY model. However, the universal momentum distribution function exhibiting nonlinear transport marks the distinction between diffusive coarsening and the approach of a nonthermal fixed point in the isolated system considered here. This underlines the importance of the universal scaling function in classifying nonthermal fixed points. Present-day experiments with quantum gases are expected to have access to the predicted bidirectional scaling.