Tunneling measurements have been performed on Nb-doped and reduced superconducting SrTi${\mathrm{O}}_3$. Beyond a certain carrier concentration, when a second conduction band gets filled, a distinctive double-gap structure is observed in Nb-doped samples. Its sharpness and anomalous temperature dependence can be related to the onset of two-band superconductivity in accordance with theoretical expectations. The observation of a single gap $\Delta \simeq 1.76 k{T}_c$ in reduced SrTi${\mathrm{O}}_3$ is attributed to enhanced interband scattering.

Electrons accelerated by the potential inside a surface emit photons with a probability related by time reversal to excitation of an electron in photoemission. Conservation of energy and momentum in the transition gives information about unfilled bands, of the same kind that angle-resolved photoemission gives for the filled bands. Particularly interesting is the possibility of using the new spin-polarized electron sources to study magnetism with the inverse photoemission technique.

A relation between the spectrum and correlation exponents of the Luttinger model is argued to be a general property of a universality class called "Luttinger liquids." The spinless fermion model equivalent to the $S=\frac{1}{2}$ Heisenberg-Ising -$\mathrm{XY}$ chain in a field is argued to belong to this class, allowing for the first time the systematic calculation of its correlation exponents.

The experimental critical behavior of the susceptibility of Li${\mathrm{Tb}}_{0.3}$${\mathrm{Y}}_{0.7}$${\mathrm{F}}_4$ is described by the power law $\chi =\Gamma {\left[\frac{(T-T_c)}{T_c}\right]}^{-\gamma }$ with $T_c=0.520\mathrm{}\pm 0.003$ K and $\gamma =1.80\mathrm{}\pm 0.04$. This behavior is dramatically different from that previously observed in LiTb${\mathrm{F}}_4$ and is evidence of a departure from marginal dimensionality when magnetic ions have been randomly replaced by nonmagnetic ions. Series expansion of ${\left(\chi T\right)}^{-1\mathrm{}}$ in powers of $T^{-1\mathrm{}}$ for a diluted Ising dipolar ferromagnet gives a good description of experimental results described in this Letter.

The critical properties of a line of transitions between a spin-glass and a ferromagnet have been determined for a series of amorphous Fe-Mn alloys. Detailed scaling analysis of the magnetization leads to the conclusion that the transition is continuous and similar to the Curie transition. The values of the critical exponents are given for the first time.

The decay of an unstable state by the stochastic time of intersection of a given threshold is described. This stochastic parameter is characterized by closed moment equations exactly soluble, whereas previous approaches, in terms of stochastic amplitudes sampled at a fixed time, led to an open hierarchy of equations requiring approximate solutions. The relevance of this new description is shown by the fit with the experimental transient fluctuations of an unstable system.

Hyperfine interactions break SU(6) symmetry in the short-range correlations between quarks and thereby give significant corrections to branching ratios for proton decay from values computed in the SU(6)-invariant limit.

The results of a perturbative quantum chromodynamic calculation are presented for two event-shape parameters in $e^{+}{e}^{-}$ annihilation up to order ${{\alpha }_s}^2$. The perturbative correction to the number of three-jet events characterized by the variable $C$ is large.

Excitation functions for fission following fusion of ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ and ${}_{}{}^{144,154}{}_{}{}^{}\mathrm{Sm}$ exhibit a strong dependence on the deformation of the target nucleus, although the fission decay selects large ($l\ge 37\hslash$) angular momenta.

Pion double charge exchange has been used to populate the double isobaric analog state in ${}_{}{}^{209}{}_{}{}^{}\mathrm{At}$ with use of the neutron-rich target ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$. The data were obtained at an energy of 292 MeV and at an angle of 5°, as the double-charge-exchange reaction mechanism has been shown to be dominated by analog transitions under these conditions in previous work on light nuclei. The measured cross section is found to be in good agreement with semiclassical predictions by Johnson.

Measurement of the relative sign of inelastic proton-channel amplitudes permits the determination of amplitude correlations. Data were obtained for $45{\frac{5}{2}}^{+}$ resonances in ${}_{}{}^{49}{}_{}{}^{}\mathrm{V}$. Although the reduced widths in each channel followed a Porter-Thomas distribution, large amplitude correlations were observed. The results are compared with the reduced-width-amplitude distribution of Krieger and Porter. This is the first direct test of the Krieger-Porter distribution.

$K\ne 0$ bands in ${}_{}{}^{158}{}_{}{}^{}\mathrm{Er}$ are obtained in Hartree-Fock calculations using a $-{\lambda }_K{J}^2$ term in the Hamiltonian. A single major shell for each proton and neutron and a surface $\delta$ interaction were used in the calculation. The large-$K$ bands have oblate shape and their Hartree-Fock field does not have time-reversal symmetry. Some of the $K\ne 0$ bands have quite low excitation energy. Their structure and the possible isomerism of the bandheads are discussed.

Laser-induced velocity-dependent light shifts have been used to compensate the Doppler broadening of an atomic transition. The unidirectional feature of this technique allowed us to observe a forward/backward asymmetry in the amplified spontaneous emission from an excited sodium vapor, switched on by a pulse of laser light.

Laser fusion requires the inward acceleration of pellet shells to very high velocity without excessive preheat of the pellet fuel. In a study of ablatively accelerated thin planar Al foils, the complete time history of the rear-surface temperatures has been determined, and the energy transport mechanisms that contribute to the heating have been evaluated.

It is shown that a likely nonlinear state for resistive interchange modes is one where stabilization is achieved by flow-induced plasma compression and in which velocity vortex structure is balanced on Ohmic dissipation. Macroscopically this is manifested as magnetic diffusion and anomalous energy transport. The results are discussed and compared with recent experiments.

Hydrodynamic response of plasma channels induced by intense propagating ion beams is examined with use of both analytical estimates and a one-dimensional radial numerical model. It is found that mega-ampere, 3-5-MeV proton beams can be propagated in deuterium background over several meters.

A mode conversion theory of the fast magnetosonic wave is compared with the experimental results in a deuterium plasma with minority hydrogen. The direct measurements of toroidal wave length, toroidal damping length, and the increase of ion temperature show that parameter dependences of ion heating are well explained by the mode conversion theory including tunneling, reflection, and absorption of the fast wave at a two-ion hybrid resonance layer.

Self-focusing filaments have been observed in a long-scale-length plasma irradiated with a 10.6-μm beam containing hot spots. Filaments were observed by use of Thomson scattering from electron plasma waves produced by two-plasmon decay in the walls of the filament, and Fresnel reflection of a visible probe beam from the density discontinuity at the filament boundary.

Compact toroids have been generated in a cylindrical resistive flux conserver. They are observed to rotate so that their major axis is perpendicular to the axis of the flux conserver. Subsequently they remain stationary and their magnetic fields decay with a time constant of about 100 μs. This is the first observation of the predicted tipping mode and its saturation when no external fields are present. The compact toroids contain toroidal fields and are initially prolate in shape.

Current limitations on the density of stabilized spin-polarized deuterium (D↓) to ∼ ${10}^{14}$ atoms/${\mathrm{cm}}^3$ are shown to arise from condensation on the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ surface and subsequent recombination. A new technique for measuring the adsorption energy is employed to provide the first such measurement for D↓ on helium, yielding $\frac{{\epsilon }_a}{k_B}=2.5\mathrm{}\pm 0.4$ K.