A BEC is a coherent collection of particles obeying Bose-Einstein statistics and all occupying the same quantum mechanical state. Since the particles in a BEC are all described by the same quantum mechanical wave function, they behave as a single quantum entity. Closely related macroscopic quantum phenomena include superfluidity and superconductivity. Though the existence of a BEC was postulated early in the previous century, it was not until 1995 that Bose-Einstein condensation was achieved in the laboratory using magnetically confined alkali atoms. For an extremely dilute gas of atoms relevant to current experiments, the transition to such a state occurs at submicrokelvin temperatures. Indeed, the coldest temperature achieved to date, three billionths of a degree above absolute zero, is required in order to form a BEC of 85 Rb atoms.

BECs offer great promise for the precision measurement applications that are at the core of NIST's mission. Several groups in the NIST Physics Laboratory are currently working on different aspects of BEC and the physics of quantum gases.

This is transfer function based. For 2D data, the low density regions are dark and the high density regions are bright. For 3D data, the low density regions are bright and the high density regions are dark.

Theoretical aspects of Bose-Einstein condensates are investigated by conducting computer simulations of their behavior. Scientific visualization techniques are employed in order to examine the large amount of data generated by simulation. Visualization of this simulated data demonstrates theoretical predictions, influences the research process, accelerates scientific understanding, and stimulates further investigation.

One focus of physics research at the National Institute of Standards and Technology (NIST) is the behavior of magnetically trapped BECs of alkali atoms that are subjected to rotation. One of the long-standing conjectures of many-body physics is that BECs of interacting particles should be a superfluid, with properties similar to those of liquid 4 He(II). One key prediction is that the confined BEC forms quantized vortices when subjected to an external torque. To explore this possibility, researchers at NIST perform computer simulations of BECs in rotating magnetic traps. Two experimental groups confirm that vortices may be produced this way in confined BECs, though there remain some interesting discrepancies between theory and experiment. Because of the large amount of data generated by simulation and the inherently small size of vortices in condensates, visualization provides not only an effective method for the detection of quantized vortices, but also for the investigation of vortex dynamics in these systems.

This visualization:

	Showed the existence of quantized vortex array structures.
	Showed the spontaneous decay of a soliton into concentric quantized vortex rings (a "snake" instability).
	Created a feedback loop from the visualization process to the simulation research.

Bose-Einstein Condensation at NIST.

Peter M. Ketcham, David L. Feder, "Visualizing Bose-Einstein Condensates", [postscript], [pdf], Computing in Science and Engineering, Volume 5, Number 1, January-February, pages 86-89, 2003.

James S. Sims, John G. Hagedorn, Peter M. Ketcham, Steven G. Satterfield, Terence J. Griffin, William L. George, Howland A. Fowler, Barbara A. am Ende, Howard K. Hung, Robert B. Bohn, John E. Koontz, Nicos S. Martys, Charles E. Bouldin, James A. Warren, David L. Feder, Charles W. Clark, B. James Filla, Judith E. Devaney, Accelerating Scientific Discovery Through Computation and Visualization, NIST Journal of Research, vol 105 (6), pp 875-894, Nov.-Dec. 2000 .

	Collaborating Scientists: Charles Clark & David Feder
	Visualization: Peter M. Ketcham
	Stereo: Steven G. Satterfield
	Video Production: Terence J. Griffin
	Parallel Computing: William L. George
	Group Leader: Judith E. Terrill