Abstract

A neutral impurity atom in superfluid helium (Hell) is now known to form a bubble like structure of surrounding helium due to the Pauli exclusion force between the electrons of impurity atom and of helium atoms. Because of the presence of bubble structure, energies and dynamics of these atoms are considerably different from those of atoms in solids, gases and other liquids. These atoms in Hell have attracted interest not only from the point of view of atomic and molecular physics, but also from their high potentiality to be applied to fundamental physics, because (1) their motion is slow enough to observe for a long period of time, (2) optical pumping techniques can be applied to these atoms to produce spin polarization and to observe magnetic resonances, (3) relaxation times for electron and nuclear spins are expected to be extremely long.

© 1996 Optical Society of America