Turbulence and Bose Condensation - Institut für Theoretische ...

Tachyon Condensation in Bose-Einstein
Condensates
Hiromitsu Takeuchi
Hiroshima University, Hiroshima, Japan
Brane cosmology proposes that the Big Bang occurs when a pair of a brane and
an anti-brane annihilate each other on collision. A phase transition accompanied
with a spontaneous symmetry breaking occurs and consequently formations of
lower- dimensional topological defects, e.g. cosmic strings, are inevitable. Such
a phase transition is triggered by the so-called "tachyon condensation", where
the existence of the tachyon is a consequence of the instability of the system.
Here we show that the tachyon condensation by a pair annihilation of a brane
and an anti-brane can be prepared in a laboratory experiment of atomic Bose-
Einstein condensates. In this system, formations of vortices from domain-wall
annihilations in three dimensions are understood as kink formations in a twodimensional
phase ordering dynamics. This study provides insights into how the
presence of the extra dimensions influences to a phase transition confined in a
restricted space embedded in higher dimensions.
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