R. B. Hallock

The Superfluid Phases of Helium 3

A comprehensive treatment of the theory of superfluid helium-3 is presented in this book. This treatment also illustrates many of the principal themes of theoretical condensed matter physics over the past two decades. The generalized BCS (Barden-Cooper-Schrieffer) pairing theory and the experimental properties of superfluid helium-3 are treated in detail. Extensive treatment of broken symmetries and their relation to macroscopic order and of the closely related topics of superflow and texture, defects in the order parameter field, and the dynamics of the nuclear spins as probed by nuclear magnetic resonance is included. This book should serve as a valuable reference for anyone working on superfluid helium-3 or on the closely related topics of unconventional superconductivity in heavy-electron metals and superfluidity of neutron star interiors.

Excitations in Liquid and Solid Helium

Introduction 1. Dynamic response functions 2. Physics of solid helium 3. Dynamic structure factor of solid helium 4. Self consistent phonon theory 5. Neutron studies of solid helium 6. Introduction to liquid 4He 7. Microscopic picture 8. Historical development of ideas 9. Observed properties of liquid 4He 10. Theory of liquid 4He 11. Nature of excitations in liquid 4He 12. Excitations in liquid 3He 13. Dynamic susceptibility of liquid 3He 14. Approximations to the dynamic susceptibility 15. Models of S(Q,omega) in liquid 3He 16. Mori and kinetic theories of liquid 3He 17. The impulse approximation 18. Final state contributions 19. Intermediate and high momentum transfer 20. Recent monographs and conference proceedings References Appendices A-C

Immunoassay based on surface plasmon oscillations.

An in situ immunoassay technique is described which is sensitive to specific binding to surface immobile antigen or antibody. The phenomena of surface plasmon oscillations are shown to be sensitive to antigen-antibody binding on a substrate. An advantage of the technique is that no molecular labeling is required. The technique allows the detection of the presence of approximately 6 X 10(8) molecules on the approximately 1 mm2 area of detection (approximately 1.5 X 10(-8) g/cm2). An elementary apparatus is described which allows the kinetics of the antigen-antibody binding to be accurately recorded in real time. A detailed example is presented. A second version of the apparatus of similar accuracy with improved temporal resolution is described.

Experimental Low Temperature Physics

Properties of solids at low temperatures properties of liquid helium reaching low temperatures stage 1 reaching low temperatures stage 2 reaching low temperatures stage 3 thermometry experimental techniques. Appendix: Laser cooling.

Review of Some of the Experimental Evidence for the Novel Wetting of Helium on Alkali Metals

We review some of the experimental evidence for the novel wetting and the behavior of helium on alkali metal substrates. We begin with a brief summary of the essential theoretical predictions, describe the initial confirmation experiments and then discuss some of the more detailed recent measurements which document the behavior of helium on these weak binding substrates.

Observation of mass transport through solid 4He

By use of a novel experimental design, one that provides for superfluid helium in contact with bulk hcp 4He off the melting curve, we have observed the DC transport of mass through a cell filled with solid 4He in the hcp region of the phase diagram. Flow, which shows characteristics of a superflow, is seen to be independent of the method used to grow the solid, but depends on pressure and temperature. The temperature dependence suggests the possibility of hysteresis.

4He Binding Energies on Single-Wall Carbon Nanotube Bundles

We have measured the temperature-programmed desorption spectrum of 4He atoms from a sample of Single-Wall Carbon Nanotubes with various initial coverages. Several Analysis techniques have been applied to the data and the results are reported here.

Capacitive Transient Detector of High Sensitivity

A capacitive detector is described which displays high sensitivity and accuracy in the measurement of transients. The device has been used in an LC circuit for studies of third sound in thin helium films. When operated in a phase‐lock mode at 21 MHz its observed sensitivity is 15 Hz per angstrom of helium film thickness; changes in average film thickness as small as 0.01 A have been detected.

Liquid structure factor measurements on3He

Results of measurements of the liquid structure factorS(k) of3He are presented. The data were taken at temperatures near0.4 K over the momentum transfer range0.15 Å−1<k<2.1 Å−1. The structure factor is compared with theoretical results and with the measurements of Achter and Meyer. We also compareS(k) for3He toS(k) for4He.

Mass flow through solid 4He induced by the fountain effect

Using an apparatus that allows superfluid liquid 4He to be in contact with hcp solid \4he at pressures greater than the bulk melting pressure of the solid, we have performed experiments that show evidence for 4He mass flux through the solid and the likely presence of superfluid inside the solid. We present results that show that a thermomechanical equilibrium in quantitative agreement with the fountain effect exists between two liquid reservoirs connected to each other through two superfluid-filled Vycor rods in series with a chamber filled with solid 4He. We use the thermomechanical effect to induce flow through the solid and measure the flow rate. On cooling, mass flux appears near T = 600 mK and rises smoothly as the temperature is lowered. Near T = 75 mK a sharp drop in the flux is present. The flux increases as the temperature is reduced below 75 mK. We comment on possible causes of this flux minimum.