PROBES OF SUPERFLUID HELIUM-3; NMR IN PERIODIC TEXTURES AND THE DRAG FORCE ON NEGATIVE IONS

Below 2.6 mK, liquid ('3)He enters a macroscopic quantum state similar to the superconducting state of electrons in a metal. The order parameter describing this state is quite complicated, in general having 18 degrees of freedom compared with only two for the superconducting case. This complication arises from the pairing of ('3)He atoms with relative orbital angular momentum 1, while the electrons in a superconductor form bound pairs with L = 0.; Two distinct phases of this 'p-wave' superfluid are observed. In the B phase there is no preferred direction for each pair's angular momentum. In the A phase all the pairs line up and the direction of their orbital angular momentum defines a preferred direction .; This thesis studies two probes of these unusual states of matter. An applied hydrodynamic flow is expected to cause the vector in the A phase to form a 'helical' spatial texture. We show that this periodic structure leads to a unique nuclear magnetic resonance (NMR) spectrum that should allow experimental identification.; Electrons injected into liquid Helium form relatively large bubble-like states with the electron at their center. These negative ions have been dragged through the superfluid phases by electric fields and their velocity has been measured. We show that simple models explain all the qualitative behavior of the drag force. In particular we identify the basic physics which explains the anisotropy of the drag force in the A phase. A new approach to the problem of impurity scattering in p-wave superfluids is presented.