Nobel Prize-winning physicist speaks at York

Internationally renowned physicist William D. Phillips (below), who has pioneered new techniques to chill atoms to extremely low temperatures, will speak at York on April 25.

His lecture, “A Bose Condensate in an Optical Lattice: Cold Atoms Meet Solid State”, is scheduled from 3 to 4pm in the Paul A. Delaney Gallery, 320 Bethune College. It is part of the Physics and Astronomy Graduate Executive (PAGE) Colloquia.

Phillips shared the 1997 Nobel Laureate in Physics, for development of methods to cool and trap atoms with laser light, with Steven Chu of Stanford University and Claude Cohen-Tannoudji of the Collège de France and the École Normale Supérieure. (Read his Nobel lecture.)

A leading researcher in laser cooling of atoms at the National Institute of Standards and Technology in Maryland, Phillips was also elected in 1997 to the National Academy of Sciences, one of the highest possible honours for an American scientist or engineer.

The cooling and trapping of atoms, a discipline that emerged in the mid-1970s with the advent of laboratory lasers, has allowed scientists to observe and measure quantum phenomena in atoms that seem to defy the physical principles governing our tangible room-temperature realm.

NIST’s renowned laser cooling and trapped-atom research program grew out of Phillips’s team’s early experiments. They discovered that atoms could be chilled well below the accepted limits, down to a few microKelvins, or just millionths of a degree, above absolute zero. This discovery paved the way for scientists to create in 1995 the first Bose-Einstein condensation, a new form of matter in which atoms fall into their lowest energy levels and merge into a single quantum state.

Phillips and his team continue to study ultra-cold trapped atoms with spin-off applications for improved accuracy in atomic clocks and in fabrication of nanostructures. For the latter, Phillips envisions using light to focus an atom laser to create what might be the basis of a next generation of ultra-small structures for electronic circuits.

Hence the subject of his talk at York University: 

“A Bose Condensate in an Optical Lattice: Cold Atoms Meet Solid State”

An atomic-gas Bose-Einstein Condensate, placed in the periodic light-shift potential of an optical standing wave, exhibits many features that are similar to the familiar problem of electrons moving in the periodic potential of a solid-state crystal lattice. Among the differences are that the BEC represents a wave function whose coherence extends over the entire lattice, with what is essentially a single quasi momentum, and that the lattice potential can be turned on and off or accelerated through space. Experiments that are not easily done with solids are often straightforward with optical lattices, sometimes with surprising results.