Examining Quantum-Degenerate Bose Gases

Albert Einstein and Satyendra Nath Bose predicted that when a gas of weakly interacting bosons - a Bose gas - was cooled to a low enough temperature, a new state of matter, a so-called Bose-Einstein condensate, would form. It took 70 years to demonstrate the transition to this state in a gas of alkali-metal atoms in 1995, garnering a Nobel prize.

A subset of Bose-Einstein condensates called spinor condensates, made of atoms that possess a spin degree of freedom, has come into focus more recently. At low enough temperatures, these systems exhibit spontaneous symmetry breaking, magnetic order, and intricate spin textures governed by the interplay of magnetism and superfluidity.

Cooling Bose gas
Image Credit: ©2011 American Physical Society

To create the image above, researchers cooled a rubidium gas to a temperature of 1.5 µK and then let it equilibrate. In the image, the magnetization of the gas is shown as the gas equilibrates. The increasing color brightness from left to right represents the growing strength of the gas’s magnetization. The different colors indicate the orientation of the magnetization. Initially, the magnetization domains point in many directions, as indicated by the variety of colors in the far left bar. Over time, large regions of the gas begin to point in the same direction so the variety of color decreases and red and pink areas predominate.

Gray arrow  "Long-time-scale dynamics of spin textures in a degenerate F=1 87Rb spinor Bose gas," Phys. Rev. A. 84, 063625 (2011)

J. Guzman 1
G.-B. Jo 1
A. N. Wenz 12

K. W. Murch 1
C. K. Thomas 1
D. M. Stamper-Kurn1 13

1 Department of Physics, University of California, Berkeley, California 94720, USA
2 Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
3 Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

This research and work was supported in part by the NSF and by a grant from the Army Research Office with funding from the Defense Advanced Research Projects Agency Optical Lattice Emulator program.

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