The dipole and Ruderman-Kittel-Kasuya-Yosida interactions between impurity spins in a superconductor are suppressed at long wavelengths. This results in a maximum in the neutron scattering at a temperature-independent wave number. It is essential to use nonlocal theory for the diamagnetic screening by the superconducting electrons. The local London approximation affects the neutron scattering cross section and overestimates the spin fluctuation energy by one order of magnitude.

By means of model calculations for an independent-electron metal, we calculate the photon absorption and emission spectra of core states, including conduction-electron relaxation. We find an x-ray edge anomaly merging into a spectrum resembling that of screened-exciton theory. Neither of these theoretical limits adequately represents the detailed structure of the exact results.

The first measurements are reported of simultaneous, transient, photoinduced optical absorption (PA) and photoconductivity (PC) in an amorphous semiconductor ($a$-${\mathrm{As}}_2$${\mathrm{Se}}_3$). Measurements in the time range 100 ns to 1 ms show that the same density of excited carriers gives rise to both effects. PA is observed only when carriers are in localized states, whereas PC is observed for both hot carriers ($\mu \tau \simeq 7\times {10}^{-12\mathrm{}}$ ${\mathrm{cm}}^2$ ${\mathrm{V}}^{-1\mathrm{}}$) and localized carriers.

Extended x-ray-absorption fine-structure measurements have been made on metal clusters of Cu and Ni which were formed by vapor deposition on amorphous carbon substrates. Small clusters of both elements show a substantial contraction of the nearest-neighbor metal-metal distance and an increase in binding energy for the onset of the $K$ absorption edge. The results are explained by the increasing surface-to-volume ratio as the cluster size decreases resulting in a more free-atom—like configuration of the metal atoms.

Very large microwave enhancements of the critical current of small superconductor—normal-metal—superconductor junctions have been observed to temperatures as low as $0.2T_c$ of the superconductor. The experimental results indicate that this enhancement is due to a strengthening of the proximity effect at the center of the normal-metal layer by the time-varying field.

It is shown that the Onsager theory, which distinguishes the Weiss field, the cavity field, and the reaction field, must be used in spin-glasses as the reaction field can be large. Along this line a simple mean-field theory permits one to recover results similar to those of Thouless, Anderson, and Palmer. Moreover the anisotropy of the reaction field explains the "two-level systems" introduced in these materials in order to explain the low-temperature properties such as hysteresis, remanence, etc.

Based on the manifestly covariant canonical formalism of quantum gravity, it is proved that gravitons must be exactly massless.

A horizontal U′(1) gauge symmetry is proposed to distinguish two fermionic generations. By extending the notion of generation structure to the Higgs system, and using anomaly-free conditions with the requirements of lepton-number conservation and proper Cabibbo structure, we determine $Y^{\prime }$ associated with U′(1), uniquely. The model can easily be generalized to account for $2^N$ ($N=1,2,\cdots$) generations.

The weak-neutral-current reaction ${\overline{\nu }}_e+d\to n+p+{\overline{\nu }}_e$ has been observed concurrently with the charged-current process ${\overline{\nu }}_e+d\to n+n+e^{+}$ using an instrumented ${\mathrm{D}}_2$O target exposed to an ${\overline{\nu }}_e$ flux of 2.5×${10}^{13}$ ${\mathrm{cm}}^{-2\mathrm{}}$ ${\sec }^{-1\mathrm{}}$. The measured neutral-current cross section, (3.8±0.9)×${10}^{-45\mathrm{}}$ ${\mathrm{cm}}^2$/${\overline{V}}_{\mathrm{e}}$, is consistent with the Weinberg-Salam model, dependent in this case only on the axial-vector contribution. The charged-current reaction cross section is (1.5±0.4)×${10}^{-45\mathrm{}}$ ${\mathrm{cm}}^2$/${\overline{V}}_{\mathrm{e}}$, in fair agreement with expectation.

An algebra of forms in Minkowski space has been constructed. A multiplication between forms is defined as an extension of the quaternionic multiplications. The algebra obtained is associative with respect to this multiplication of order 16. Duality is expressed as (new) multiplication by a basis element. Vector identities in the algebra lead to a number of new trace identities. A new derivative operator expresses the four Maxwell equations in an especially transparent form.

Analytic formulas are derived for the energy, longitudinal-, and transverse-momentum distributions of "soft" radiation for $e^{+}{e}^{-}\to q\overline{q}$+ gluons in a Bloch-Nordsieck approach to quantum chromodynamics. A comparison with the data of Hanson et al. obtained at SPEAR is made for the resulting hadronic longitudinal- and transverse-momentum distribution.

The most recent CERN intersecting storage-rings data on very large transverse momenta show that the velocity of sound in hadronic matter increases from $\simeq 1\sqrt{7} \mathrm{to} \simeq 1\sqrt{3.5}$, implying a phase transition from a strongly interacting (hadron) phase to a weakly interacting (parton?) phase.

We deduce that if $f\left(cos\theta \right)$ has nonnegative partial waves, then ${\left[\frac{f\left(cos\theta \right)}{f\left(1\right)\mathrm{}}\right]}^2<~\frac{1}{3}+\frac{2}{3}\frac{f\left(\frac{1}{2}\right(3\mathrm{}{cos}^2\theta -1\left)\right)}{f\left(1\right)\mathrm{}}$ for $-1\mathrm{}<~cos\theta <~1$. Applying this, we show that recent determinations of the ${\pi }^{-}p$ slope parameter for $\mathrm{}\left|t\right|\mathrm{}<~0.04$ (${\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ at 100 GeV/c at CERN, together with those at larger $\mathrm{}\left|t\right|\mathrm{}$ at Fermilab, imply a substantial violation of unitarity, though each determination by itself is consistent with unitarity.

We propose a modified definition of hadronic jets in quantum chromodynamics which is more selective than the Sterman-Weinberg criterion. It prohibits any two jet streams from having appreciably different energies. Our more restrictive definition provides new tests of quantum chromodynamics in high-energy experiments. We illustrate this idea for two-"quark"-jet configurations in $e^{+}{e}^{-}\to \mathrm{hadrons}$ and for two-"gluon"-jet production. The necessity of exponentiating perturbative jet predictions is also discussed.

The cross section for fusion of ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$+${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ is found to differ markedly from that of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$+${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ for bombarding energies in the range 3 to 9 times the fusion barrier. This difference exceeds that expected on the basis of calculated or measured nuclear density distributions for these nuclei.

The hyperfine structure of OH in the $A{{}_{}{}^2{}_{}{}^{}\Sigma _{\frac{1}{2}}^{}{}_{}{}^{}}^{+}$ state has been measured by exciting a molecular beam with cw intracavity frequency-doubled dye-laser radiation. The splittings are 778 MHz for $N^{\prime }=0\mathrm{} \mathrm{and} 200 \mathrm{to} 500$ MHz for $1<~N^{\prime }<~5$. The values for the hyperfine and $\rho$ doubling are $b+\frac{1}{3}c=777.8\mathrm{}\pm 2.0$ MHz, $c=165.8\mathrm{}\pm 2.8$ MHz, and $\gamma =7.13\mathrm{}\pm 0.03$ GHz. Also the hyperfine splitting of OD in the $N^{\prime }=0\mathrm{}$ state has been measured yielding $b+\frac{1}{3}c=119\mathrm{}\pm 2$ MHz.

A physically sensible orthogonality procedure for use in atomic calculations is described. For clarity we focus on the orthogonalization of ejected-election orbitals to bound target orbitals for calculation of single ionization of multielectron atoms. A simple application to electron ionization of helium is given to illustrate the general analytic properties of the procedure and its practicability.

Inverse-dee- and square-shaped equilibria are observed by experimentally mapping the magnetic-flux plot as a function of time in a tokamak with a 4-null poloidal divertor. Inverse-dee equilibria are observed to be unstable to the vertical magnetohydrodynamic axisymmetric instability on a time scale ∼1000 poloidal Alfvén times. Square equilibria are stable on the time scale available for observation. Instability growth is apparently slowed by field-shaping hoop and wall passive stabilization.

X-ray intensities from over 1000 reflections in single-crystal ${\mathrm{V}}_3$Si at 300, 78, and 13.5 K, previously obtained by one of us (J.-L.S.) have been analyzed for anharmonicity when ${\lambda }^{-1\mathrm{}}sin\theta >0.7\mathrm{}$ ${\mathrm{\AA }}^{-1\mathrm{}}$ where diffraction occurs from core electrons only. At 78 K we find $〈{\mu }^2〉$ and $〈{\mu }^4〉$ moments for V which are ∼ 50% and 500% larger, respectively, than expected for a harmonic lattice, and evidence for localization of the V atoms off the lattice sites by ∼0.2 Å. No evidence of such large anharmonicity is found for Si atoms at all three temperatures.

New structural models for 2×1 and 4×2 reconstructed (100) surfaces of Si determined from energy-minimization claculations are presented. The optimal 2×1 and 4×2 structures are found to correspond to asymmetric dimer geometries with partially ionic bonds between surface atoms, resulting in semiconducting surface electronic bands. The atomic and electronic structures for the 2×1 and 4×2 reconstructed surfaces are discussed.