The mass of a vortex in a superfluid

David Thouless
UW Physics

The inertial mass of a vortex in a classical fluid has been studied over more than a century, but there is still disagreement about the mass of a quantized vortex in a neutral superfluid.  Statements by good physicists can be found in the literature which range from saying it is negligible to saying that it is infinite.  Experimental information is also uncertain. In recent work with James Anglin (Kaiserslautern) we have got some clean theoretical results which should resolve these uncertainties.  By studying the motion of a vortex driven in a circle by a rotating pinning potential we can identify the Magnus force and the centrifugal force, and have verified that the expression used by Gordon Baym and Elaine Chandler to determine the mass agrees with ours.  In contrast to earlier work we do not find that the compressibility of the fluid leads to an infinite mass, and we do find that the mass is sensitive to the nature of the pinning force, depending logarithmically on the range of the pinning force.