Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Relaxation of Bosons in One Dimension and the Onset of Dimensional
  Crossover   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.

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The categories of this paper are: cmp-lg
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The categories of this paper are: chem-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: atom-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: econ
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The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-th
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The categories of this paper are: supr-con
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The categories of this paper are: hep-th