32 research outputs found
Realization of Discrete Quantum Billiard in 2D Optical Lattices
We propose the method for optical visualization of Bose-Hubbard model with
two interacting bosons in the form of two-dimensional (2D) optical lattices
consisting of optical waveguides, where the waveguides at the diagonal are
characterized by different refractive index than others elsewhere, modeling the
boson-boson interaction. We study the light intensity distribution function
averaged over direction of propagation for both ordered and disordered cases,
exploring sensitivity of the averaged picture with respect to the beam
injection position. For our finite systems the resulting patterns reminiscent
the ones set in billiards and therefore we introduce a definition of discrete
quantum billiard discussing the possible relevance to its well established
continuous counterpart
Optically induced orientational transitions in nematics with planar alignment
Theoretical study of dynamical phenomena induced by a linearly polarized
plane wave incident perpendicularly on a planar aligned nematic layer with the
light intensity as the control parameter is reported. We find the threshold of
the Optically Induced Freedericksz Transition for the planar state as a
function of the problem parameters. It occurs that the threshold is
substantially lower than that expected before. Above the primary instability
the director settles either to a stationary or to an oscillatory states
depending on a thickness of the layer. These states become unstable at a
secondary threshold through a heteroclinic bifurcation and the director settles
to a new stationary distorted state
Interaction induced fractional Bloch and tunneling oscillations
We study the dynamics of few interacting bosons in a one-dimensional lattice
with dc bias. In the absence of interactions the system displays single
particle Bloch oscillations. For strong interaction the Bloch oscillation
regime reemerges with fractional Bloch periods which are inversely proportional
to the number of bosons clustered into a bound state. The interaction strength
is affecting the oscillation amplitude. Excellent agreement is found between
numerical data and a composite particle dynamics approach. For specific values
of the interaction strength a particle will tunnel from the interacting cloud
to a well defined distant lattice location.Comment: 4 pages, 4 figure