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Title: Thermally induced rotons in two-dimensional dilute Bose gases

Journal Article · · Physical Review. B, Condensed Matter and Materials Physics
DOI:https://doi.org/10.1103/PHYSREVB.73.1· OSTI ID:20787996
;  [1]
  1. Institut fuer Theoretische Physik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin (Germany)

We show that rotonlike excitations are thermally induced in a two-dimensional dilute Bose gas as a consequence of the strong phase fluctuations in two dimensions. At low momentum, the rotonlike excitations lead for small enough temperatures to an anomalous phonon spectrum with a temperature-dependent exponent reminiscent of the Kosterlitz-Thouless transition. Despite the anomalous form of the energy spectrum, it is shown that the corresponding effective theory of vortices describes the usual Kosterlitz-Thouless transition. The possible existence of an anomalous normal state in a small temperature interval is also discussed.

OSTI ID:
20787996
Journal Information:
Physical Review. B, Condensed Matter and Materials Physics, Vol. 73, Issue 10; Other Information: DOI: 10.1103/PhysRevB.73.104515; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
Country of Publication:
United States
Language:
English