Event DetailsEvent Dates: Thursday, July 16, 2015 - 4:00pmSeminar Location: JILA X317Speaker Name(s): Dan Stamper-KurnSpeaker Affiliation(s): University of California - Berkeley Seminar Type/SubjectScientific Seminar Type: JILA Public SeminarEvent Details & Abstract: The quantum degenerate spinor Bose gas is a new material characterized by both magnetic and superfluid order. Like other ordered magnetic materials, the gas supports magnon excitations. We have developed techniques to create and image magnon excitations in ferromagnetic rubidium spinor condensates. At short times after their creation, magnons are observed to propagate coherently, allowing us to measure their energy dispersion with high precision through interferometry. Using high-resolution spin-sensitive imaging, we measure the magnon spectrum to be gapped due to magnetic dipole interactions (as it often is in magnetic solids). At longer times, the magnons thermalize. We show that this thermalization allows one to measure the temperature of highly degenerate gases, and to reduce this temperature further by a new form of evaporative cooling. Upon recooling the gas, the thermalized magnons condense. I will present recent measurements that explore such magnon condensation. Preceded by a reception at 3:30 pm in the Hbar cafe.