Quantum Institute: Visitor Schedule

The Quantum Lunch is regularly held on Thursdays in the Theoretical Division Conference Room, TA-3, Building 123, Room 121.

The organizing committee includes Ryan O. Behunin (T-4 & CNLS), Malcolm Boshier (P-21), Adolfo del Campo (T-4 & CNLS), Michael Di Rosa (C-PCS), Ivar Martin (T-4), Changhyun Ryu (P-21), Rolando D. Somma (T-4), Christopher Ticknor (T-1), and Wojciech H. Zurek (T-4).

For more information, or to nominate a speaker, contact Adolfo del Campo.

To add your name to the Quantum Lunch email list, contact Ellie Vigil.

Thursday, January 31, 2013
12:30 PM - 2:00 PM

Speaker: Kevin Wright (Dartmouth College)

Technical Host: Changhyun Ryu

TOPIC: SQUID-like phenomena Bose-Einstein condensate "circuits"

Abstract
Quantum fluids often exhibit remarkable properties which can make them useful for constructing sensors and other devices, such as SQUID magnetometers and superfluid helium gyroscopes. I will describe recent experiments conducted at the Joint Quantum Institute with a dilute gas of ultracold sodium atoms in a ring-shaped geometry. In these experiments we were able to control the (quantized) circulation state of a toroidal atomic Bose-Einstein condensate with a rotating "weak link" created by a repulsive optical dipole potential. This system is directly analogous to a superconducting loop in an external magnetic field, where the loop is interrupted by a weak link with a dynamically tunable current-phase relation. We have observed phenomena such as discrete phase slips between circulation states, and hysteresis in the total "rotational flux" as a function of the applied "rotational flux". I will also discuss prospects for using SQUID-like atom "circuits" for rotation sensing, and as a means for investigating the exotic properties of macroscopic quantum systems.