Houston, TX 77005
4:00 p.m. Friday, March 22, 2013
On Campus | Alumni
Ultracold atoms provide an ideal platform to study quantum many-body phenomena in a clean, controlled environment. This control, or tunability of the microscopic interactions and bulk geometry, permits the emulation of more complex quantum systems, but also offers a context to study completely new many-body Hamiltonians. Dilute Bose-Einstein condensates (BECs) of strongly dipolar atoms are no exception. In appropriate trapping geometries, these systems exhibit a roton-maxon character in their quasiparticle dispersion relation, much like that in superfluid Helium-4, though emerging from a different physical origin. Like in Helium-4, the roton in dipolar BECs plays a critical role in the superfluid behavior of these systems. Moreover, these rotons can be made strongly anisotropic and can have strong finite-size dependence, making the dipolar BEC an ideal testing ground for roton physics beyond the realm of Helium-4. In this seminar, I will present a host of novel phenomena related to the roton in dipolar BECs, including novel superfluid behavior and collapse dynamics. Interestingly, the roton-induced collapse of dipolar BECs can be carefully exploited to provide a clear signature of its presence in a dipolar BEC, which has yet to be confirmed experimentally. Additionally, I will discuss how the roton emerges in a binary, or two-component dipolar BEC, where it plays a profound role in the quantum transition to an immiscible phase.