Trapping Long-Lifetime Excitons in a Two-Dimensional Harmonic Potential
  We report an important step forward for the goal of unambiguous observation of Bose-Einstein condensation of excitons in semiconductors. We have demonstrated a system in which excitons live for microseconds, much longer than their thermalization time, move over distances of hundreds of microns, and can be trapped in a harmonic potential exactly analous to the traps for atomic condensates. We also report recent results of a new method for observing evidence of Bose-Einstein condensation, by angular resolution of the emitted luminescence. 
D.W. Snoke, Y. Liu, Z. Voros, L. Pfeiffer, K. West