Nematic Order by Disorder in Spin-2 Bose-Einstein Condensates

Journal Article · Fri May 11 00:00:00 EDT 2007 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.98.190404· OSTI ID:20951348

Turner, Ari M; Demler, Eugene ^[1]; Barnett, Ryan ^[2]; Vishwanath, Ashvin ^[3]

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1. Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)
2. Department of Physics, California Institute of Technology, MC 114-36, Pasadena, California 91125 (United States)
3. Department of Physics, University of California, Berkeley, California 94720 (United States)

We show that quantum and thermal fluctuations in spin-2 Bose-Einstein condensates lift the accidental degeneracy of the mean-field phase diagram. Fluctuations select the uniaxial (square biaxial) nematic state for scattering lengths a{sub 4}>a{sub 2} (a{sub 4}<a{sub 2}). Paradoxically, the order is stronger at higher temperatures. For spin-2 {sup 87}Rb and {sup 23}Na, a continuous Ising-type transition is predicted on raising the magnetic field, from a fluctuation stabilized uniaxial state to a field stabilized square biaxial order state. This is a promising experimental system to realize the ''order-by-disorder'' phenomenon.

• OSTI ID: 20951348
• Journal Information: Physical Review Letters, Vol. 98, Issue 19; Other Information: DOI: 10.1103/PhysRevLett.98.190404; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BOSE-EINSTEIN CONDENSATION
FLUCTUATIONS
MAGNETIC FIELDS
MEAN-FIELD THEORY
PHASE DIAGRAMS
RUBIDIUM 87
SCATTERING LENGTHS
SODIUM 23
SPIN