We propose a novel mechanism for Kapitza conductance between phonons in solid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ quasiparticles in dilute ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ liquid mixtures. This conductance is large only when the interface between the liquid and solid is rough. We have measured this conductance using a dynamical method, and have obtained results in agreement with the theory.

We report magnetoresistance studies on narrow aluminum wires of width $0.2 \mu \mathrm{m}<W<\mathrm{}0.6\mathrm{} \mu \mathrm{m}$ which demonstrate clearly for the first time the one-dimensional localization effects predicted by Thouless, where the theory is generalized to include spin-orbit scattering. The electron inelastic-scattering rate is the same as in two-dimensional films, determined by known inelastic mechanisms. The dependence of resistance on temperature for $2 \mathrm{K}<T<\mathrm{}20\mathrm{} \mathrm{K}$ is also well explained by the theory.

We report the first definitive measurements of extended x-ray absorption fine structure (EXAFS) made by monitoring the direct photoelectron emission as a function of photon energy. We have measured EXAFS associated with the Mn $3p$ and F $2s$ core levels in evaporated films of Mn${\mathrm{F}}_2$ and found good agreement with bulk transmission EXAFS associated with the Mn $1s$ level. Photoelectron EXAFS makes possible surface-sensitive structural determinations using vacuum uv radiation on a virtually unlimited range of systems.

This Letter reports on the first optically detected electron-nuclear double-resonance (ENDOR) measurements of a paramagnetic semiconductor defect in which ligand hyperfine interactions could be resolved. In semi-insulating GaAs: Cr the ENDOR lines of the first-shell ${}_{}{}^{75}{}_{}{}^{}\mathrm{As}$ neighbors of the regular tetrahedral As${\mathrm{As}}_4$-antisite defect could be detected and analyzed. The ENDOR investigation reveals that at least one other As${\mathrm{As}}_4$-antisite complex contributes to the same ESR spectrum.

A Monte Carlo method for obtaining exact ground-state properties of a class of Hubbard Hamiltonians is described. Results are presented for two special cases, nearest-neighbor Coulomb and on-site interactions, where previous exact results are known. The straightforward applicability of the method to a wider variety of interactions is demonstrated.

We show that a proper description of the temperature dependence of the spin-lattice relaxation rate of low-spin hemoproteins and ferredoxin requires that both the fractal structure of the protein backbone (polypeptide chain) and the cross connections (H bridges) between segments of the folded chain be taken into account. Within this picture the fracton dimensionality $d_{\mathrm{fr}}$ (recently introduced by Alexander and Orbach), the fractal dimensionality $d_f$, and the experimental noninteger exponent $n$ of Stapleton et al. (spin-lattice relaxation rate $\frac{1}{T_1}\propto T^n$) become satisfactorily consistent.

We show that axion emission from neutron stars is the dominant energy-loss mechanism for a range of values of the Peccei-Quinn symmetry-breaking scale ($F$) not excluded by previous constraints. This gives the possibility of obtaining a better bound on $F$ from measurements of surface temperature of neutron stars.

A light gluino is not presently excluded experimentally if the lightest of the gluino-containing ($R-$) hadrons are long lived. In this case the properties of $R$-hadrons are very different than has been previously assumed. Strategies for their detection are suggested.

Neutron oscillations introduce nonlinear behavior in the magnetic field dependence of the neutron energy. In principle these minute effects are observable if regeneration problems can be overcome, but general statistical arguments render this approach noncompetitive with direct observation of the antineutron.

The partial rate differences between particle and antiparticle decaying into their corresponding $\mathrm{CP}$-conjugate states for the charm and beauty mesons $F^{\pm }$, $D^{\pm }$, ${B_u}^{\pm }$, and ${B_c}^{\pm }$ are estimated. Some decays have appreciable partial rate differences, notably $B_u^{-}\to {\pi }^0{K}^{-}$, $D^{-}{D}^{0*}$ and $B_c^{-}\to K^{-}{\bar{D}}^0$, ${\pi }^{-}{\bar{D}}^0$, ${\pi }^0{D}^{-}$. The uncertainties involved in such analysis are discussed.

We explore some properties of dense matter in Skyrme's chiral soliton model and show that at high densities the energy density varies as $n^{\frac{4}{3}}$, where $n$ is the baryon density. This is quite different from the behavior of conventional nuclear models, but is very similar to that of quark matter. The maximum mass of neutron stars constructed of such matter is significantly lower than that for most other versions of dense matter and may account for the absence of neutron stars in many extended supernova remnants. The phase transition to quark matter is expected to be softened considerably by such a nuclear-matter model.

Charged-particle-$\gamma$-ray coincidences have been measured following the fusion of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=60\mathrm{}$ MeV. Particle energy and angular distributions in coincidence with $\gamma$ rays detected with the Max Planck Institut-Gesellschaft für Schwerionenforschung $4\pi$ $\gamma$-ray spectrometer are measured, from which it is possible to estimate the time at which high-energy photons are emitted in the compound-nuclear decay process. In addition, information is obtained about the $\gamma$-ray multiplicity associated with the energetic photons.

Four signals characterizing the Balmer-alpha radiation resulting from 40-80-keV collisions of ${\mathrm{H}}^{+}$ on He were measured as a function of an applied transverse electric field. Detailed analysis allowed the axially symmetric density matrix of the $\mathrm{H} \mathrm{}(n=3\mathrm{})\mathrm{}$ atom formed in the collision to be obtained. The imaginary parts of the off-diagonal density-matrix elements are presented as the distribution of the electronic current density in the atom. One of the first-order moments ${〈\overrightarrow{\mathrm{A}}\times \overrightarrow{\mathrm{L}}〉}_z^s$ of the current distribution is given.

The behavior of strong magnetosonic waves with $\omega >{\omega }_{\mathrm{ci}}$ (${\omega }_{\mathrm{ci}}=\frac{q_{i}B}{m_{i}c}$) is investigated in oblique propagation with particle simulation. Strong ion and electron heatings versus the angle [$\theta =(\overrightarrow{\mathrm{k}},{\overrightarrow{\mathrm{B}}}_0)$] are found for $\theta <90\mathrm{}$°. Ion heating peaks at a particular angle but disappears below a critical angle ${\theta }_{t_i}$; electron heating sets in below a second critical angle ${\theta }_{t_e}$. The phenomena exhibit unexpected structure with $\theta$.

By converting a coherent wave to a random-phased wave, the intensity profile on a target becomes easily controllable. Planar as well as spherical targets were irradiated for the first time by the random-phased wave. The targets were uniformly accelerated without being affected by the small-scale intensity nonuniformities. The $\frac{3}{2}$-harmonic emission shows that the plasma waves at $\frac{n_c}{4}$ are only weakly excited in a spherical plasma. Irradiation with short-wavelength, random-phased beams will be suitable for compression.

A self-consistent description is obtained for the low-frequency evolution of a plasma, the electromagnetic field that confines it, and the amplitude of a high-frequency antenna-driven field. The ponderomotive energy of the system is related to the antenna reactive energy. Equilibrium equations and a variational principle for stability are given in terms of ion and electron ponderomotive forces, magnetization current, and self-consistent modification of the high-frequency field.

This paper gives measurements of frequency-dependent ultrasonic damping, $\alpha$, at frequencies, $f$, between 2 and 21 MHz in the smectic-$A$ phase of terephthal-$\mathrm{bis}$-$p$-$p^{\prime }$-butylaniline. There is no trace of the considerable increase in $\frac{\alpha }{f^2}$ between 2 and 10 MHz reported by Bhattacharya and Ketterson, working on the same compound with a similar pulse technique. Our results question the existence of anharmonic effects within the frequency range investigated.

An elastic Ginzburg-Landau theory which includes strain and strain-gradient contributions is formulated for inhomogeneous strain fields associated with interface boundaries, heterophase inclusions, and transformation precursors. For proper purely ferroelastic materials of $D_{4h}$ symmetry, an explicit kink-type solitary-wave solution describing a moving coherent ($1\bar{1}0$) twin boundary is obtained.

A unified description of martensitic pseudoelasticity based on the Laves-Cahn model of deformation pseudotwins is presented. In particular, we treat the puzzling problem of "rubber elasticity" in disordered alloys. The dynamics of twin-boundary motion reflects the nucleation and growth characteristics of the decay of a metastable state. The model is amenable to direct experimental test by time-dependent x-ray diffraction.

It is demonstrated that diffusion of deuterons and protons in crystalline rutile, Ti${\mathrm{O}}_2$, can be induced near room temperature by breaking of the O-H bond with electron irradiation and sweeping of these hydrogenic species along the $c$ axis by an electric field.