Spin nematic order in antiferromagnetic spinor condensates (Dr. T. Zibold)
- Datum: 26.11.2015
- Uhrzeit: 13:30 - 15:00
- Vortragende(r): Dr. Tilman Zibold, Laboratoire Kastler-Brossel / Collège de France, Paris
- Raum: Herbert Walther Lecture Hall
- Gastgeber: MPQ, Laser Spectroscopy Division
Large spin systems can exhibit unconventional types of magnetic ordering different from the ferromagnetic or N\'eel-like antiferromagnetic order commonly found in spin 1/2 systems.
Spin-nematic phases, for instance, do not break time-reversal invariance
and their magnetic order parameter is characterized by a second rank
tensor with the symmetry of an ellipsoid. Here we show direct
experimental evidence for spin-nematic ordering in a spin-1
Bose-Einstein condensate of sodium atoms with antiferromagnetic
interactions. In a mean field description this order is enforced by
locking the relative phase between spin components. We reveal this
mechanism by studying the spin noise after a spin rotation, which is
shown to contain information hidden when looking only at averages. The
method should be applicable to high spin systems in order to reveal
complex magnetic phases.