Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A liquid-gas transition for bosons with attractive interaction in one
  dimension   We consider a one dimensional system of $N$ bosons interacting via an
attractive Dirac delta function potential. We place the bosonic quantum
particles at thermal equilibrium in a box of length $L$ with periodic boundary
conditions. At large $N$ and for $L$ much larger than the diameter of a two
particle bound state, we predict by numerical and analytical studies of a
simple model derived from first principles that the system exhibits a first
order phase transition in a high temperature, non-degenerate regime. The higher
temperature phase is an almost pure atomic gas, with a small fraction of
dimers, a smaller fraction of trimers, etc. The lower temperature phase is a
mesoscopic or macroscopic bound state that collects all the particles of the
system with the exception of a small gaseous fraction composed mainly of atoms.
We term this phase, which is the quantum equivalent of the classical bright
soliton, a liquid.---Nous considerons, en dimension un, une assemblee de $N$
particules quantiques bosoniques interagissant par un potentiel de Dirac
attractif, a l'equilibre thermique dans une boite de quantification de longueur
L avec des conditions aux limites periodiques. Pour de grandes valeurs de N, et
lorsque L est bien superieur au diametre de l'etat dimere dans l'espace reel,
nous predisons, par etude numerique et analytique d'un modele simple mais
deduit des premiers principes, que le systeme presente, a haute temperature
c'est-a-dire dans le regime non degenere, une transition du premier ordre entre
deux phases. La phase privilegiee a haute temperature est un gaz presque pur
d'atomes, avec une faible fraction de dimeres, et des fractions encore plus
faibles de trimeres, etc. La phase qui la supplante a moins haute temperature
est un etat lie mesoscopique ou macroscopique que nous qualifions de liquide,
equivalent quantique du soliton brillant de la theorie de champ classique, et
qui renferme toutes les particules du systeme, a l'exception d'une petite
fraction gazeuse composee essentiellement d'atomes.

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The categories of this paper are: mtrl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: nlin
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The categories of this paper are: astro-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: supr-con
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The categories of this paper are: q-alg
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The categories of this paper are: math
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The categories of this paper are: hep-lat
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The categories of this paper are: comp-gas
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The categories of this paper are: funct-an
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-th
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The categories of this paper are: math-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ex