Novel Behavior in Solid 4He: New Tricks in an Old Dog

 

Robert Hallock

University of Massachusetts

 

 

In the early 1970’s it was predicted that solid helium might display some unusual superfluid-like behavior.  Several years ago interest in the behavior of solid 4He was rekindled, first by John Goodkind's group and shortly later in a more dramatic fashion by Eunseong Kim and Moses Chan who showed that when solid helium was put into rotation some of it seemed to be left behind.  Indeed, solid helium has over the past few years shown a variety of very unusual, even surprising, phenomena. Some of these will be briefly reviewed and then experiments that demonstrate the transmission of atoms through the solid in response to an applied chemical potential difference, which may deepen the mystery about the solid, will be described in more detail.