Long Lived Excited States in Bose Einstein Condensates
(by William P. Reinhardt)
We introduce and overview the recent experimental and theoretical work on
gaseous Bose-Einstein condensates (BECs) which have been extensively
studied in the lab since 1995, and the experimental work which led to the
2001 Nobel Prize in Physics for Ketterle, Weiman, and Cornell. Gaseous
BECs are a fully "visible" quantum fluid (i.e. you can simply take its
picture!) which undergoes phase transitions of many types, and has
extraordinary tunablity of all parameters including density, coupling
constants (via a "resonance" effect) , and even of the number and types of
"components" and thus provides a remarkable laboratory for testing
theoretical and mathematical modelling of superfluids and
superconductivity, in a manner not open to traditional condensed matter
experiment. Many types of long lived excitations of these systems may be
thought of as "resonances." These include solitons, vortices (both of
which are well described by the famous Non Linear Schrodinger equation to
zeroth order), and large scale Schrodinger Cats. The decay mechanisms of
some of these are understood, others not, so there is ample room for
development of new physical and mathematical approaches, including
many-body effects.