Dynamical Universal Behavior in Quantum Chaotic Systems

We discover numerically that a moving wave packet in a quantum chaotic billiard will always evolve into a quantum state, whose density probability distribution is exponential. This exponential distribution is found to be universal for quantum chaotic systems with rigorous proof. In contrast, for the corresponding classical system, the distribution is Gaussian. We find that the quantum exponential distribution can smoothly change to the classical Gaussian distribution with coarse graining.Comment: 4 figure

Critical correlations in an ultracold Bose gas revealed by means of a temporal Talbot-Lau interferometer

We study experimentally the critical correlation in an ultra-cold Bose gas with a temporal Talbot-Lau (TL) interferometer. Near the critical temperature, we observe a bi-modal density distribution in an ultra-cold Bose gas after the application of the TL interferometer. The measured fraction of the narrower peak in the density distribution displays a clear peak within the critical regime. The peak position agrees with the critical temperature calculated with the finite-size and interaction corrections. The critical exponents are extracted from the peak and they agree with the critical exponents for the correlation length.Comment: 5 pages, 3 figures and supplemental materia