Bidirectional universal dynamics in a spinor Bose gas close to a nonthermal fixed point
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 macrosc...
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| Main Authors: | , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
18 March 2019
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| In: |
Physical review
Year: 2019, Volume: 99, Issue: 3 |
| ISSN: | 2469-9934 |
| DOI: | 10.1103/PhysRevA.99.033611 |
| Online Access: | Verlag, Volltext: https://doi.org/10.1103/PhysRevA.99.033611 Verlag, Volltext: https://link.aps.org/doi/10.1103/PhysRevA.99.033611 
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| Author Notes: | Christian-Marcel Schmied, Maximilian Prüfer, Markus K. Oberthaler, and Thomas Gasenzer |
| Summary: | 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. |
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| Item Description: | Gesehen am 28.06.2019 |
| Physical Description: | Online Resource |
| ISSN: | 2469-9934 |
| DOI: | 10.1103/PhysRevA.99.033611 |