Speaker
Paul Goldbart (U. of Illions Urbana Champaign)
(University of Illions Urbana Champaign)
Description
The self-organization of a Bose-Einstein condensate in a
transversely pumped optical cavity is a process akin to
crystallization: when pumped by a laser of sufficient
intensity, the coupled matter and light fields evolve,
spontaneously, into a spatially modulated pattern, or
crystal, whose lattice structure is dictated by the geometry
of the cavity. In cavities having multiple degenerate
modes, the quasi-continuum of possible lattice arrangements,
and the continuous symmetry breaking associated with the
adoption of a particular one, give rise to phenomena such as
phonons, defects, and frustration. A nonequilibrium
field-theoretic approach enables the exploration of the
self-organization of a Bose-Einstein condensate in a pumped,
lossy optical cavity. At nonzero temperatures, this
organization occurs via a fluctuation-driven first-order
phase transition of the Brazovskii class; the transition
persists to zero temperature and crosses over into a quantum
phase transition. The field-theoretic approach also enables
the investigation of the role of nonequilibrium fluctuations
in the self-organization transition, as well as the
nucleation of ordered-phase droplets, the nature and
energetics of topological defects, supersolidity in the
ordered phase, and the possibility of frustration effects
controlled by the cavity geometry.
