Relaxation of bosons in one dimension and the onset of dimensional crossover
Chen Li, Tianwei Zhou, Igor Mazets, Hans-Peter Stimming, Frederik S. Møller, Zijie Zhu, Yueyang Zhai, Wei Xiong, Xiaoji Zhou, Xuzong Chen, Jörg Schmiedmayer
SciPost Phys. 9, 058 (2020) · published 22 October 2020
- doi: 10.21468/SciPostPhys.9.4.058
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Abstract
We study ultra-cold bosons out of equilibrium in a one-dimensional (1D) setting and probe the breaking of integrability and the resulting relaxation at the onset of the crossover from one to three dimensions. In a quantum Newton's cradle type experiment, we excite the atoms to oscillate and collide in an array of 1D tubes and observe the evolution for up to 4.8 seconds (400 oscillations) with minimal heating and loss. By investigating the dynamics of the longitudinal momentum distribution function and the transverse excitation, we observe and quantify a two-stage relaxation process. In the initial stage single-body dephasing reduces the 1D densities, thus rapidly drives the 1D gas out of the quantum degenerate regime. The momentum distribution function asymptotically approaches the distribution of quasimomenta (rapidities), which are conserved in an integrable system. In the subsequent long time evolution, the 1D gas slowly relaxes towards thermal equilibrium through the collisions with transversely excited atoms. Moreover, we tune the dynamics in the dimensional crossover by initializing the evolution with different imprinted longitudinal momenta (energies). The dynamical evolution towards the relaxed state is quantitatively described by a semiclassical molecular dynamics simulation.
Cited by 22
Authors / Affiliations: mappings to Contributors and Organizations
See all Organizations.- 1 2 Chen Li,
- 1 3 Tianwei Zhou,
- 2 4 Igor Mazets,
- 3 Hans-Peter Stimming,
- 2 Frederik Skovbo Møller,
- 5 Zijie Zhu,
- 6 Yueyang Zhai,
- 1 Wei Xiong,
- 1 Xiaoji Zhou,
- 1 Xuzong Chen,
- 2 Jörg Schmiedmayer
- 1 Vienna Center for Quantum Science and Technology [VCQ]
- 2 北京大学 / Peking University [PKU]
- 3 Istituto Nazionale di Ottica [INO]
- 4 Universität Wien / University of Vienna
- 5 Eidgenössische Technische Hochschule Zürich / Swiss Federal Institute of Technology in Zurich (ETH) [ETH Zurich]
- 6 北京航空航天大学 / Beihang University [BUAA]
- Austrian Science Fund (FWF) (through Organization: Fonds zur Förderung der wissenschaftlichen Forschung / FWF Austrian Science Fund [FWF])
- National Key Research and Development Program of China (through Organization: Ministry of Science and Technology of the People's Republic of China [MOST])
- National Natural Science Foundation of China [NSFC]
- Wiener Wissenschafts Forschungs und Technologiefonds / Vienna Science and Technology Fund [WWTF]