Stochastic quantization is used to obtain upper and lower bounds on the vacuum expectation value of ${\mathrm{\phi }}^{\mathrm{n}}$ in a cutoff λ${\mathrm{\phi }}^{\mathrm{n}}$ scalar theory in d dimensions. These determine the behavior of 〈${\mathrm{\phi }}^{\mathrm{n}}$〉 as the cutoff is removed. The results are given by formulas which depend on whether the values of n and d define a perturbatively superrenormalizable, strictly renormalizable, or nonrenormalizable theory.

The study of electric quadrupole transitions from the ground state into symmetric states and into states of mixed symmetry in the deformed nucleus ${}_{}{}^{156}{}_{}{}^{}\mathrm{Gd}$ by inelastic electron scattering has been used to derive effective neutron and proton boson charges for the $E2\mathrm{}$ operator in the framework of the interacting-boson model. The values for $e_{\pi }$ and $e_{\nu }$ differ at most by 30% in the rotational limit.

The density-gradient expansion of the fermion exchange hole is analyzed in real space. Unlike the local-density approximation, the second-order gradient-expansion approximation is found to violate two important properties of the exact hole: The exact hole is negative everywhere, and represents a deficit of one electron. Imposition of these exact constraints leads to an accurate new density functional for the exchange energy. Residual errors in the exchange energy for atoms are about 1% of this quantity. The new functional approximation may be generalized to include correlation.

Fast-wave current drive is demonstrated in the Princeton ACT-I toroidal device. The fast Alfvén wave, in the range of high ion-cyclotron harmonics, produced 40 A of current from 1 kW of rf power coupled into a plasma by a fast-wave loop antenna. This wave excites a steady current by damping on the energetic tail of the electron distribution function in the same way as lower-hybrid current drive, except that fast-wave current drive is appropriate for higher plasma densities.

It is shown that evaporant ions from pellet-injected plasmas are accelerated to energies considerably in excess of the background thermal energies. This energy transduction in pellet evaporation is a hydrodynamic ion-acceleration process that may provide a useful new method of plasma energy control.

The speed and attenuation of second sound in the $B$ phase of superfluid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ near the transition temperature were measured at pressures of 18.2, 21.3, and 24.4 bars under zero applied magnetic field. The second sound was detected by use of a resonance method (frequency ∼ 1 Hz) and Peshkov transducers. The measured speed of second sound is in good agreement with the expected value. The measured quality factor is compared with a recent theory on the second viscosity coefficient.

The anchoring energy at the interface between the nematic liquid crystal 4-$n$-pentyl-4′-cyanobiphenyl (5CB) and a glass plate treated by oblique evaporation of SiO is studied by measurement of the torque exerted on the surface by the nematic subject to an orienting magnetic field. The anchoring energy is sharply reduced as the clearing temperature is approached. The experiment provides the first direct evidence of a strong reduction of the surface order parameter for this system in the anisotropic phase.

We develop a systematic boundary-layer-type formalism for diffusion-controlled dendritic growth, which yields an expression for the shape of steady-state needle solutions valid at large undercoolings. Both physical and analytical considerations suggest the general existence of a continuous family of steady-state needlelike solutions of the heat-flow equations. Simple modifications of the boundary-layer model of Ben-Jacob et al. exhibit this behavior.

A generic phase diagram is proposed for stepped ($11m$) surfaces of fcc metals, which describes the roughening transition and subsequent changes of the nature of the rough phase in terms of a sequence of universal values for the roughness parameter $x_1(T, m)$. From a detailed analysis of atom-beam diffraction profiles of Ni(115), for $100 \mathrm{K}<T<\mathrm{}900\mathrm{} \mathrm{K}$, it is concluded that Ni(115) is rough in this temperature interval. The roughening temperatures of Ni(113) and Ni(001) are predicted to be 200 ± 50 K and well above 420 K, respectively. Near 420 K, islands appear in the rough (115) surfaces in addition to the meandering steps.

We have measured fine structure extending 400 eV above the Fermi energy in the x-ray bremsstrahlung isochromat spectrum of Cu. This spectrum is shown to be extremely similar at high energies to an extended x-ray-absorption fine-structure (EXAFS) spectrum of Cu. We conclude that the EXAFS model for high-energy conduction-electron propagation in solids is applicable to bremsstrahlung isochromat spectroscopy and that an EXAFS-like procedure is suitable for the quantitative analysis of extended-range bremsstrahlung isochromat spectral data.

We present a new result which shows the transitions from chaos to order and again to chaos as the coupling parameter between two nonlinearly coupled oscillators of a Hamiltonian system is varied continuously from $-\infty \mathrm{to} +\infty$. By exploiting the symmetry of the system, we show that there is no general correspondence between the classical chaotic motion and the Gaussian-orthogonal-ensemble distributions of the energy-level fluctuations of the corresponding quantum system.

We report the first observation of quantized energy levels for a macroscopic variable, namely the phase difference across a current-biased Josephson junction in its zero-voltage state. The position of these energy levels is in quantitative agreement with a quantum mechanical calculation based on parameters of the junction that are measured in the classical regime.

Data are presented on the temperature-dependent escape rates of a macroscopic system, a SQUID containing a highly damped Josephson junction, from its metastable state. These data provide the first quantitative confirmation of recent predictions of the exponential effects of temperature and damping on quantum tunneling in macroscopic systems in contrast to previously reported discrepancies. Predicted quantum corrections to thermally activated escape at high temperatures are not observed.

By the writing of the translational Langevin equation in a rotating frame of reference (1,2,3)′ and the rotational equation in the usual moving frame (1,2,3), it is shown that the statistical correlation between the angular and linear center-of-mass motion of a diffusing asymmetric top can be described naturally and in detail. Computer simulation is used to illustrate the symmetry class and time dependence of many new types of autocorrelation and cross-correlation functions suggested by the structure of these equations.

We present measurements of the differential cross section for the production of massive muon pairs in 225-GeV/c ${\pi }^{-}$-nucleus collisions. We have used the data between the $\psi$ and $\Upsilon$ resonances in the framework of the Drell-Yan quark-antiquark annihilation model to predict the behavior of the cross section in the high-mass ($m_{\mu \mu }>11\mathrm{}$ GeV/${\mathit{c}}^2$) region. The data are consistent with this extrapolation provided that a QCD leading-logarithmic evolution is included in the structure functions.

The magnetic moment 1.876(5)${\mathrm{\mu }}_{\mathit{N}}$ of 4.77-min ${}_{}{}^{207}{}_{}{}^{}\mathrm{Tl}$, the only heavy nucleus with a doubly magic core plus a single $s_{\frac{1}{2}}$ particle or hole, was measured from the hfs by collinear fast-beam laser spectroscopy at ISOLDE (isotope separator at the CERN synchrotron). The result is of theoretical importance as a test case for core polarization since the nuclear structure is relatively simple and the orbital part of the magnetic moment, including strong pion-exchange contribution, is expected to be zero.

Electrons with energies in the range of 100 to 600 eV have been observed to be emitted following 0.1-3.2-MeV collisions of Kr ions with Xe targets. Coincidence measurements between these electrons and the scattering ions determine the impact-parameter dependence for this electron emission. Although these data lie outside the conventional region of applicability of the one-electron molecular-orbital model, they are remarkably consistent with such molecular-orbital calculations. These Kr-Xe data are similar in nature to those for Kr-Kr collisions which previous authors have interpreted differently.

The Doppler-free, two-photon $5d^{10}6s{}_{}{}^2{}_{}{}^{}S_{\frac{1}{2}}^{}{}_{}{}^{}-5\mathrm{}{d}^{9}6s^2{}_{}{}^2{}_{}{}^{}D_{\frac{5}{2}}^{}{}_{}{}^{}$ transition in singly ionized Hg, attractive as an optical-frequency standard, has been observed for the first time on a small number of ${}_{}{}^{198}{}_{}{}^{}\mathrm{Hg}_{}^{+}{}_{}{}^{}$ ions confined in a radio-frequency trap. The radiative lifetime of the ${}_{}{}^2{}_{}{}^{}D_{\frac{5}{2}}^{}{}_{}{}^{}$ state and the absolute wave number of the two-photon transition were measured to be 0.090(15) s and 17 757.152(3) ${\mathrm{cm}}^{-1\mathrm{}}$, respectively. Optical amplitude-modulation sidebands, induced by the secular (thermal) motion of the harmonically bound ions, were observed also for the first time.

Single-photon laser spectroscopy of ${\mathrm{H}}_2$ from the metastable $c{}_{}{}^3{}_{}{}^{}\Pi _{\mathrm{u}}^{}{}_{}{}^{}$ state has been used to study triplet $\mathrm{nd}$ autoionizing Rydberg states, $n\approx 10-20$. We observe a new and extensive spectrum which shows a well-resolved fine structure due to interaction of the Rydberg electron with the extended cord. An ab initio Hund's case-$d$ model is shown to predict the transition frequencies in isolated portions of the spectrum. In general, however, extensive channel interactions will necessitate a multichannel quantum-defect-theory analysis.

We report the first observation of the autoinizing triplet $\mathrm{nd}$ series of ${\mathrm{H}}_2$ covering the region from $n=10\mathrm{}$ to the series limit. The autoionizing states are produced by excitation of ${\mathrm{H}}_2$ $c{}_{}{}^3{}_{}{}^{}\Pi _{\mathrm{u}}^{-}{}_{}{}^{}$ molecules in a fast (1 keV) beam with a frequency-doubled pulsed dye laser, and the resulting ${\mathrm{H}}_2^{+}$ ions are detected. We have also resolved members of the high-lying $\mathrm{nd}$ series ($25<n<\mathrm{}35\mathrm{}$) converging to the lowest vibrational state of the ${\mathrm{H}}_2^{+}$ ion by field ionization. A qualitative interpretation of the spectra in terms of a noninteracting single-channel Rydberg electron model is given.