Projects per year
Abstract
We explore the statistical behaviour of the discrete nonlinear Schrödinger equation as a test bed for the observation of negativetemperature (i.e. above infinite temperature) states in Bose–Einstein condensates in optical lattices and arrays of optical waveguides. By monitoring the microcanonical temperature, we show that there exists a parameter region where the system evolves towards a state characterized by a finite density of discrete breathers and a negative temperature. Such a state persists over very long (astronomical) times since the convergence to equilibrium becomes increasingly slower as a consequence of a coarsening process. We also discuss two possible mechanisms for the generation of negativetemperature states in experimental setups, namely, the introduction of boundary dissipations and the free expansion of wavepackets initially in equilibrium at a positive temperature.
Original language  English 

Article number  023032 
Number of pages  13 
Journal  New Journal of Physics 
Volume  15 
Issue number  2 
DOIs  
Publication status  Published  19 Feb 2013 
Keywords
 discrete breathers
 optical waveguides
 BEC
 negative temperatures
Projects
 1 Finished

Superresolution optical microscopy via nonlinear selffocusing
EPSRC (Engineering and Physical Sciences Research Council)
1/01/11 → 28/02/15
Project: Research