Vortex Mass
Григорий Ефимович Воловик
Abstract
Abstract The mass (inertia) of an object is determined as the response of the momentum of the object to its velocity. This chapter discusses the inertia of an object moving in the quantum vacuum of the Galilean quantum liquid. If it is a foreign object like a 3He atom moving in the quantum vacuum of superfluid 4He, then in addition to its bare mass the object acquires an extra mass, since it involves some part of the superfluid vacuum into motion. If the object is an excitation of the vacuum, like a vortex, all its mass is provided by the liquid. In addition to the associated hydrodynamic mass, which is similar to associated mass of external body moving in the liquid, there are two more contributions to a vortex mass. The ‘relativistic’ mass is the consequence of effective metric in superfluids. It is obtained as vortex energy divided by square of speed of sound, which plays the role of speed of light. In fermionic superfluids the Kopnin mass is added, which results from the fermion zero modes in the vortex core. This mass is related to peculiar phenomenon in quantum field theory. In the limit of smooth core these bound states behave as chiral massless fermions in the presence of magnetic field, and the additional vortex mass results from the non-zero density of states in magnetic field.