Measurement of the Canonical Equation of State of a Weakly Interacting 3D Bose Gas.

Using a multiple-image reconstruction method applied to a harmonically trapped Bose gas, we determine the equation of state of uniform matter across the critical transition point, within the local density approximation. Our experimental results provide the canonical description of pressure as a function of the specific volume, emphasizing the dramatic deviations from the ideal Bose gas behavior caused by interactions. They also provide clear evidence for the nonmonotonic behavior with temperature of the chemical potential, which is a consequence of superfluidity and Bose-Einstein condensation. The measured thermodynamic quantities are compared to mean-field predictions available for the interacting Bose gas. The limits of applicability of the local density approximation near the critical point are also discussed, focusing on the behavior of the isothermal compressibility.

Single-shot reconstruction of the density profile of a dense atomic gas.

Partial transfer absorption imaging (PTAI) of ultracold atoms allows for repeated and minimally-destructive measurements of an atomic ensemble. Here, we present a reconstruction technique based on PTAI that can be used to piece together the non-uniform spatial profile of high-density atomic samples using multiple measurements. We achieved a thirty-fold increase of the effective dynamic range of our imaging, and were able to image otherwise saturated samples with unprecedented accuracy of both low- and high-density features.

Observation of Magnetic Solitons in Two-Component Bose-Einstein Condensates.

We experimentally investigate the dynamics of spin solitary waves (magnetic solitons) in a harmonically trapped, binary superfluid mixture. We measure the in situ density of each pseudospin component and their relative local phase via an interferometric technique we developed and as such, fully characterize the magnetic solitons while they undergo oscillatory motion in the trap. Magnetic solitons exhibit nondispersive, dissipationless longtime dynamics. By imprinting multiple magnetic solitons in our ultracold gas sample, we engineer binary collisions between solitons of either the same or opposite magnetization and map out their trajectories.

Laboratory automation: a challenge for the 1990s.

THERE IS TREMENDOUS PRESSURE ON INDUSTRY AND LABORATORIES TO DEVELOP INCREASINGLY COMPLEX PROCUCTS: for example catalysts, chiral chemicals, drugs and ceramics; conform to regulations; cope with increasingly severe competition; and meet steadily increasing costs. It is difficult, in this situation, to remain productive and competitive. It is vital to be equipped with, and be able to use appropriately, all the suitable methodologies and technologies. Working methods and personnel have to be appropriate. The future depends on three interdependent domains: automation in the broadest sense of the word, instrumentation and information systems. The easy work has already been done. Between 1984 and 1990, it was a question of going from nothing to something; now, it is necessary to increase and optimize.THEREFORE, THE CRUCIAL QUESTION IS NOW: 'how can we go quicker in experimentation and acquire more knowledge, while spending less money?' One solution is to use all the aspects of automation (robotics, instrumentation, data). Successful laboratory automation depends.on: shortened time to market; improved efficiency/cost ratio; motivation/competence/ expertise; communication; and knowledge acquisition. This paper examines some of the major technological areas of application.