1. The Center for Ultracold Atoms at MIT and Harvard Quantum noise as probe of many-body systems Advisory Committee Visit, May 13-14, 2010

2. Quantum noise Classical measurement: collapse of the wavefunction into eigenstates of x Histogram of measurements of x

3. Quantum noise as a probe of many-body systems Low dimensional condensates in equilibrium

4. x z Time of flight Experiments with 2D Bose gas Hadzibabic, Dalibard et al., Nature (2006) Experiments with 1D Bose gas Hofferberth et al. Nature Physics (2008)

5. Interference of independent 1d condensates Theory: Altman, Imambekov, Polkovnikov, Gritsev, Demler Experiments: Hofferberth et al., Nature Physics (2008) Observation of quantum fluctuations in 1d Bose gas Probe of higher order correlation functions Shot to shot fluctuations of fringe contrast as a probe of many-body correlations contrast normalized by the average value Thermal noise Quantum noise Distribution function Quantum and Thermal fringe contrast

6. Quantum noise as a probe of many-body systems Dynamics of low dimensional systems

7. Dynamics in 1d: Ramsey interference Interaction induced collapse of Ramsey fringes. time Ramsey fringe visibility Only weak spin echo was observed in experiments Experiments: Widera, Gritsev et al. PRL (2008)

8. Distribution function of fringe contrast as a probe of many-body dynamics Short segments Long segments T. Kitagawa et al., PRL in press

9. Distribution function of fringe contrast as a probe of many-body dynamics Preliminary results by J. Schmiedmayer’s group Short segmentsLong segmentsSplitting one condensate into two.