A Green's function which is asymptotically exact in the Kondo regime is presented. The temperature-dependent susceptibility of the Anderson model is calculated from this Green's function and is found to be in excellent agreement at all temperatures with the results of renormalization-group theory. The formalism presented suggests a microscopic physical mechanism for the scaling and universality of the thermodynamic properties found in renormalization-group theory.

Vector Bäcklund transformations which relate solutions of the vacuum Einstein equations having two commuting Killing fields are introduced. Such transformations generalize those found by Pohlmeyer in connection with the nonlinear $\sigma$ model. A simple algebraic superposition principle, which permits the combination of Bäcklund transforms in order to get new solutions, is given. The superposition preserves the asymptotic flatness condition, and the whole scheme is manisfestly O(2,1) invariant.

Data are presented on the Gross-Llewellyn Smith sum rule obtained from combined narrow-band neon and Freon bubble-chamber neutrino-antineutrino experiments. Remarkably no significant deviation from the parton-model prediction for the sum rule is observed at very low values of $q^2\lesssim 1$ Ge${\mathrm{V}}^2$. Limits on the effective QCD scale parameter $\Lambda$ and on the magnitude of the twist-4 correction are set. The best fit, neglecting higher-twist contributions, gives $\Lambda ={92}_{-36\mathrm{}}^{+20\mathrm{}}$ MeV.

Recent deep-inelastic muon-scattering data from iron and deuterium targets are interpreted as evidence that the distribution of quarks in iron differs markedly from that in isolated nucleons. Some sources of the difference are suggested.

A class of "realistic" supergravity grand-unified-theory models possessing two $W$-inos and two $Z$-inos which lie above and below $W^{\pm }$ and $Z^0$ mass, respectively, are examined. A lower bound on the $W$-ino mass of ≃ 30 GeV is obtained with an upper bound of ≃ 250 GeV on the Higgs mass. It is shown that the $Z^0$ decays prominantly into two $W$-inos if the mass of the $W-\mathrm{ino}<~\frac{M_W}{2}$. The superpartners of quarks and leptons are shown to be approximately degenerate and in some models have mass ≲ 100 GeV.

The neutron polarization in the reaction ${}_{}{}^2{}_{}{}^{}\mathrm{H}(\gamma , n)\mathrm{H}$ is calculated by incorporating the two-body charge- and current-density effects in the traditional theory. The calculations are carried out for a number of recent and old two-nucleon potentials. Clear evidence is provided that even at very low energies a serious discrepancy between theory and experiment exists.

All natural-parity states of ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ have been studied with high accuracy with the ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}({}_{}{}^7{}_{}{}^{}\mathrm{Li}, t\gamma ){}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ coincidence and ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}(\alpha , \gamma ){}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ radiative-capture reactions. The four-particle, two-hole $0_2^{+}$, $1^{-}$, $2_3^{+}$, and $3_3^{-}$ states deexcite with consecutive enhanced $E1\mathrm{}$ and $E2\mathrm{}$ cross-over transitions having $B\left(E1\mathrm{}\right)\mathrm{}\simeq {10}^{-2\mathrm{}}$ Weisskopf units (W.u.) and $B\left(E2\mathrm{}\right)\mathrm{}\simeq 20$ W.u. These data suggest the existence of an $\alpha$ +${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ dipole band in ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ similar to those discussed recently by Iachello and Jackson.

It is shown that the electron-cyclotron maser instabilities may readily be excited in a plasma with a loss-cone distribution when the electron temperature exceeds a few tens of kiloelectronvolts. The growth rate is typically a few percent of the electron-cyclotron frequency. The appearance of the instability can be avoided by proper control of the plasma density.

The density, heat capacity, and electrical resistivity for the alloy K-Cs at the stoichiometric composition ${\mathrm{K}}_2$Cs have been measured through the solid and liquid states. A new singular point $T_c=258\mathrm{}$ K has been detected above the well-known freezing point $T=253.5\mathrm{}$ K. This is the rare case of a critical point being close to the solidification transition and is also the only case known of a miscibility gap in the liquid state of a mixture that exhibits full solubility below its solidus line.

On the basis of a previously proposed mean-field model of solid solutions under irradiation, asymptotic expressions are derived for the dispersion curves of the eigen-concentration modes in such solutions. Specific features of small-angle scattering from such solutions are anticipated, as well as the possibility for time-periodic concentration oscillations.

It is shown that in the limit of continuously flexible, Gaussian polymer chains, the first-order rate for end-to-end reactions, $k_{\mathrm{cyc}}\mathrm{}\left(t\right)\mathrm{}$, scales as the fundamental reptation time, ${\tau }_{\mathrm{rep}}$. At short times $t<\mathrm{}{\tau }_{\mathrm{rep}}$, $k_{\mathrm{cyc}}\mathrm{}\left(t\right)\mathrm{}\to \left(\frac{0.333}{{\tau }_{\mathrm{rep}}}\right){\left(\frac{t}{{\tau }_{\mathrm{rep}}}\right)}^{-\frac{1}{4}}$, while at long times, $k_{\mathrm{cyc}}\left(\infty \right)=\frac{0.363}{{\tau }_{\mathrm{rep}}}$. The analysis also gives the exact chain-length-dependent memory and reaction-rate functions in the discrete case of bead-rod chains obeying the earthworm equations of Doi and Edwards.

The first observations of the third vibrational overtone of molecular hydrogen are reported. This overtone, long sought in high-pressure gaseous hydrogen studies, is important in the interpretation of some of the observed features in the spectra of outer giant planets. The observations carried out in hcp solid parahydrogen should provide the much needed incentive for increased theoretical understanding of the simplest of the molecular solids.

A scheme is proposed whereby a coupling can be achieved between the spin-wave and zero-sound modes in a neutral Fermi liquid; the technique should permit a detailed study of the spin-wave spectrum.

An efficient Monte Carlo procedure is applied to the study of the kinetics of low-and high-$Q$-state Potts models quenched from an initial high-temperature ($T\gg T_c$) state to very low temperatures ($T\simeq 0$). After an initial transient period, the mean domain size, $R$, increases algebraically with time as $R\sim C{t}^n$. The exponent $n$ decreases from ½ for $Q=2\mathrm{}$ (Ising model) to 0.38 for large $Q$. The change in $n$ is attributed to a coalescence process which becomes increasingly effective with decreasing $Q$. For large $Q$, the prefactor $C$ is proportional to $Q^{\frac{1}{2}}$.

X-ray $L$ absorption spectra were measured for the rare-earth metals Sm and from Gd to Lu. The data are compared with single-particle band-structure calculations over an energy range of about 100 eV. The one-electron theory describes the white line and the near-edge structure strikingly well. At higher energies, although all features of the experimental spectra are reproduced by the calculation, the actual placement of the features shows discrepancies, which point to a limitation in the one-electron description.

Evidence for superconductivity in ${\mathrm{}(\mathrm{B}\mathrm{E}\mathrm{D}\mathrm{T}-\mathrm{T}\mathrm{T}\mathrm{E})\mathrm{}}_4$${\left(\mathrm{R}\mathrm{e}{\mathrm{O}}_4\right)}_2$ [where BEDT-TTF is bis (ethylenedithiolo)tetrathiafulvalene] near 2 K for pressures above 4 kbar is reported. This is the first unambiguous observation of superconductivity in a sulfur-donor organic system. At higher pressures the transition temperature decreases rapidly, $\frac{d{T}_c}{\mathrm{dP}}\sim -0.3\mathrm{}$ K/kbar. At low pressures this material exhibits a first-order metal-insulator transition, postulated to result from a change in the arrangement of the anions which are ordered at room temperature.

From Faraday rotation measurements, evidence is given that irradiation, with near-infrared light, of the cobalt aluminosilicate glass in its spin-glass state hastens the relaxation of the thermoremanent magnetization. Experimental data on the dependence of this photomagnetic anneal with radiation power, light wavelength, and polarization are discussed within a simple phenomenological model.

Magnetoresistance measurements of thin Al films ($1\frac{\Omega }{\square }<R_{\square }<60\mathrm{}\frac{\Omega }{\square }$) between 2.5 and 30 K are reported and analyzed within the framework of localization theories. The influence of superconducting fluctuations is felt far above the critical temperature, in agreement with the theory of Larkin. The electron inelastic scattering is inversely proportional to the temperature in accordance with Abrahams et al. Its absolute value, which agrees with phase-slip-center measurements, is 1 order of magnitude larger than predicted.

This Letter reports on the first discrete-lattice calculation of positron surface states on the surfaces of Al. The authors reproduce the observed values and anisotropy of the binding energies on clean surfaces, and predict the surface-state lifetimes. The temperature-independent lateral diffusion constant is calculated. Monovacancies on surfaces are predicted not to trap positrons. The effect of ordered chemisorbed monolayers of oxygen is investigated: Oxidation makes the surface state unstable with respect to positronium emission.

The phenomenon of dimensional reduction in quantum theories of gravity is studied. In the five-dimensional Kaluza-Klein model, the one-loop effective potential as a function of $g_{55}$ is computed. When the distance around the fifth dimension is larger than the Planck length, the loop expansion is reliable. The result leads to a force tending to make the fifth dimension contract to a size on the order of the Planck length. This can be interpreted as a gravitational version of the Casimir effect in electrodynamics.