Dynamics of a cold trapped ion in a Bose-Einstein condensate

We investigate the interaction of a laser-cooled trapped ion (Ba$^+$ or Rb$^+$) with an optically confined $^{87}$Rb Bose-Einstein condensate (BEC). The system features interesting dynamics of the ion and the atom cloud as determined by their collisions and their motion in their respective traps. Elastic as well as inelastic processes are observed and their respective cross sections are determined. We demonstrate that a single ion can be used to probe the density profile of an ultracold atom cloud.Comment: 4 pages, 5 figure

Coherent optical transfer of Feshbach molecules to a lower vibrational state

Using the technique of stimulated Raman adiabatic passage (STIRAP) we have coherently transferred ultracold 87Rb2 Feshbach molecules into a more deeply bound vibrational quantum level. Our measurements indicate a high transfer efficiency of up to 87%. As the molecules are held in an optical lattice with not more than a single molecule per lattice site, inelastic collisions between the molecules are suppressed and we observe long molecular lifetimes of about 1 s. Using STIRAP we have created quantum superpositions of the two molecular states and tested their coherence interferometrically. These results represent an important step towards Bose-Einstein condensation (BEC) of molecules in the vibrational ground state.Comment: 4 pages, 5 figure

Development and Validation of an Instructional Program To Teach Observational and Recording Skills in Behavior Modification

A multimedia program for teaching observational and recording skills was developed and validated using a modified research and development model. The program consisted of two slide carousels (192 slides) with accompanying cassette tape and workbook and three supersound 8 mm cassettes with accompanying manual and monitor\u27s guide. These materials are available through the Instructional Media Center of the Exceptional Child Center, Utah State University, Logan, Utah. The model employed two phases to determine program effectiveness. Phase I was concerned with the development and formative evaluation of program materials and procedures. In Phase II the program was validated under field conditions. The effectiveness of the program was determined by comparing experimental and control groups on post-criterion test scores. The participants also filled out a questionnaire rating various aspects of the program. Validation of the program was conducted at the Utah State University Exceptional Child Center. Four Special Education and one Psychology classes were used for the main field test. The sample population was randomly selected from class roll lists of the accessible population and consisted of 40 subjects, 20 assigned to the experimental group and 20 to the control group. Each experimental subject was assigned to two sessions in order to complete the program, each session being approximately 1\ hours in length. The sessions were a maximum of four days apart, and for the majority of students were completed within a 24-hour time period. The hypothesis that the experimental group would have significantly higher posttest mean scores than the control group was tested. An F value of 129.38 was significant at the .001 level for the total program. These results support the hypothesis. On the Student Feedback Form the program was rated overall at 4.93 on a five-point scale as being highly interesting, of value to them, and an efficient way to present this material. The subjects reached criterion on the data collecting tasks presented. It was concluded from the post-criterion test and the feedback form results that this multimedia program was effective in teaching the basic concepts of observing, defining, and recording behavior

Cruising through molecular bound state manifolds with radio frequency

The emerging field of ultracold molecules with their rich internal structure is currently attracting a lot of interest. Various methods have been developed to produce ultracold molecules in pre-set quantum states. For future experiments it will be important to efficiently transfer these molecules from their initial quantum state to other quantum states of interest. Optical Raman schemes are excellent tools for transfer, but can be involved in terms of equipment, laser stabilization and finding the right transitions. Here we demonstrate a very general and simple way for transfer of molecules from one quantum state to a neighboring quantum state with better than 99% efficiency. The scheme is based on Zeeman tuning the molecular state to avoided level crossings where radio-frequency transitions can then be carried out. By repeating this process at different crossings, molecules can be successively transported through a large manifold of quantum states. As an important spin-off of our experiments, we demonstrate a high-precision spectroscopy method for investigating level crossings.Comment: 5 pages, 5 figures, submitted for publicatio

Atom-molecule dark states in a Bose-Einstein condensate

We have created a dark quantum superposition state of a Rb Bose-Einstein condensate (BEC) and a degenerate gas of Rb$_2$ ground state molecules in a specific ro-vibrational state using two-color photoassociation. As a signature for the decoupling of this coherent atom-molecule gas from the light field we observe a striking suppression of photoassociation loss. In our experiment the maximal molecule population in the dark state is limited to about 100 Rb$_2$ molecules due to laser induced decay. The experimental findings can be well described by a simple three mode model.Comment: 4 pages, 6 figure

Visual Analytics for Understanding Spatial Situations from Episodic Movement Data

Continuing advances in modern data acquisition techniques result in rapidly growing amounts of geo-referenced data about moving objects and in emergence of new data types. We define episodic movement data as a new complex data type to be considered in the research fields relevant to data analysis. In episodic movement data, position measurements may be separated by large time gaps, in which the positions of the moving objects are unknown and cannot be reliably reconstructed. Many of the existing methods for movement analysis are designed for data with fine temporal resolution and cannot be applied to discontinuous trajectories. We present an approach utilizing Visual Analytics methods to explore and understand the temporal variation of spatial situations derived from episodic movement data by means of spatio-temporal aggregation. The situations are defined in terms of the presence of moving objects in different places and in terms of flows (collective movements) among the places. The approach, which combines interactive visual displays with clustering of the spatial situations, is presented by example of a real dataset collected by Bluetooth sensors

Pure Gas of Optically Trapped Molecules Created from Fermionic Atoms

We report on the production of a pure sample of up to 3x10^5 optically trapped molecules from a Fermi gas of 6Li atoms. The dimers are formed by three-body recombination near a Feshbach resonance. For purification a Stern-Gerlach selection technique is used that efficiently removes all trapped atoms from the atom-molecule mixture. The behavior of the purified molecular sample shows a striking dependence on the applied magnetic field. For very weakly bound molecules near the Feshbach resonance, the gas exhibits a remarkable stability with respect to collisional decay.Comment: 4 pages, 5 figure