We present the structure and results of an analysis of the asymptotic behavior of nonlinear, asymmetric, metric perturbations near the Cauchy horizon inside a Kerr black hole. This analysis suggests that metric perturbations, to all orders in the perturbation expansion, are finite and small at the Cauchy horizon, even though their gradients (and the curvature) diverge there. Accordingly, objects which fall into a realistic rotating black hole a long time after the collapse will not be crushed by a tidal gravitational deformation as they approach the curvature singularity.

We present a systematic linear analysis of the perturbations induced by cosmic strings in cold dark matter. We calculate the power spectrum and find that the strings produce a great deal of power on small scales. We show that the perturbations on interesting scales are the result of many uncorrelated string motions, which indicates a more ‘‘Gaussian’’ distribution than was previously supposed.

We use numerical simulations to study the spatial structure of a quark and an antiquark in the imaginary-time excitations which mediate the Debye screening of color singlet sources in the high-temperature phase of QCD. We find that these correlation functions are very similar to the zero-temperature wave functions of the corresponding particles. This result contrasts with results on the ρ and nucleon screening lengths for these sources, which are well described by a gas of free or weakly interacting quarks.

The aspon model of spontaneous CP violation solves the strong CP problem and gives a new mechanism for weak CP violation. It predicts a vector quark doublet Q and a gauge boson A. The QQ¯ production at Fermilab and the Superconductive Super Collider (SSC) is calculated, production of a QQ¯A final state at the SSC is computed, and signatures of Q and A are discussed.

The origin and consequences of pseudospin symmetry in nuclear physics, which is exact for an oscillator potential with one-body orbit-orbit (${\nu }_{\mathit{l}\mathit{l}}$) and spin-orbit (${\nu }_{\mathit{l}\mathit{s}}$) interaction strengths in the ratio μieq2${\nu }_{\mathit{l}\mathit{l}}$/${\nu }_{\mathit{l}\mathit{s}}$=0.5, are considered. Specifically, the ${\nu }_{\mathit{l}\mathit{s}}$≊4${\nu }_{\mathit{l}\mathit{l}}$ condition is consistent with relativistic mean-field results and a pseudo LS coupling scheme. When deformation dominates, pseudospin extends to pseudo SU(3), which is applicable to superdeformation.

The polarization of quasifree Λ hyperons produced by the (${\mathrm{\pi }}^{+}$${\mathit{K}}^{+}$) reaction on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and on the deuteron was measured for the first time. The asymmetry of pions from weak decay of the Λ hyperon was used to determine the polarization. The polarization for the deuterium target was found to be consistent with that for the elementary n(${\mathrm{\pi }}^{+}$,${\mathit{K}}^{+}$)Λ reaction. The polarization of the Λ produced by the quasifree process from ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ is consistent with that for the elementary reaction, which demonstrates that the spin characteristics of the elementary reaction are not modified by the nuclear medium.

The multifragment emission of ‘‘completely characterized’’ events in the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$${+}^{40}$Ca system at 35 MeV/nucleon has been compared to the predictions of several models. The observed multifragment emission is not in agreement with models based on conventional statistical binary decay, but is in agreement with both a simultaneous multifragmentation model and a sequential emission model in which expansion is treated.

Zero-degree dσ/dE and ${\mathit{d}}^2$σ/dE dΩ cusp-shape and yield variations indicate substantial electron-loss–to–continuum (ELC) contributions in the electron-capture–to–continuum (ECC) spectra obtained with bare H and He ∼1 MeV/nucleon projectiles on hydrocarbon molecules. An intramolecular geometrical outscattering model of secondary collisions has been developed to calculate the ELC fraction of the cusp ${\mathit{f}}_{\mathrm{ELC}}$, extract the separate ECC and ELC contributions from measured projectile velocity frame cusp contours, and predict a nominal ${\mathit{Z}}_{\mathit{P}}^3$ dependence for ELC yields in agreement with experiments in our velocity range.

Fluoresence-excitation spectroscopy near 84.5 nm has been used to measure the threshold for the dissociation limit of ${\mathrm{H}}_2$(B’ ${}_{}{}^1{}_{}{}^{}\mathrm{\Sigma }_{\mathit{u}}^{+}{}_{}{}^{}$)=H(1s)+H(2s) at 118 377.06±0.04 ${\mathrm{cm}}^{\mathrm{-}1}$. This yields a value of ${\mathit{D}}_0$(${\mathrm{H}}_2$)=36 118.11±0.08 ${\mathrm{cm}}^{\mathrm{-}1}$ for the dissociation energy of the ground electronic state X${(}^1$${\mathrm{\Sigma }}_{\mathit{g}}^{+}$) of ${\mathrm{H}}_2$, in agreement with the latest theoretical calculation which includes nonadiabatic, relativistic, and radiative corrections. When combined with recent determinations of the ionization energy of ${\mathrm{H}}_2$ the present ${\mathit{D}}_0$(${\mathrm{H}}_2$) leads to the value ${\mathit{D}}_0$${\mathrm{H}}_2^{+}$)=21 379.36±0.08 ${\mathrm{cm}}^{\mathrm{-}1}$, also in good agreement with theoretical values.

Quantum frequency conversion, a process with which an input beam of light can be converted into an output beam of a different frequency while preserving the quantum state, is experimentally demonstrated for the first time. Nonclassical intensity correlation (≃3 dB) between two beams at 1064 nm is used as the input quantum property. When the frequency of one of the beams is converted from 1064 to 532 nm, nonclassical intensity correlations (≃1.5 dB) appear between the up-converted beam and the remaining beam. Our measurements are in excellent agreement with the quantum theory of frequency conversion. The development of tunable sources of novel quantum light states seems possible.

We report the observation of ordered capillary-wave states generated by three and four standing plane waves. The pattern produced by the four standing plane waves forms the first quasicrystal observed in a fluid dynamical system. The states are observed at aspect ratios above 45, and for amplitudes below the amplitude at which a square-symmetric state is formed. We also report the observation of a capillary-wave state generated by three radial waves.

Pressure fluctuations measured during slow drainage in a two-dimensional porous model exhibit sudden jumps that identify bursts where the invasion front proceeds abruptly. The pressure-jump size distribution is observed to be exponential. The nonscaling dynamics created fractal fronts and invaded regions described by invasion percolation. A new modified invasion percolation algorithm includes invasion dynamics. A capacitive volume associated with each interface throat results in a crossover from power-law behavior to an exponential pressure jump distribution consistent with observations.

Ion temperature measurements, time resolved to 10 μs, have been made in the Madison Symmetric Torus (MST) reversed-field pinch with a five-channel charge-exchange analyzer. The ion temperature, ${\mathit{T}}_{\mathit{i}}$≊300 eV for I=360 kA, increases by as much as 100% during discrete dynamo bursts in MST discharges. Magnetic-field fluctuations in the range 0.5–5 MHz were also measured. Structure in the fluctuation frequency spectrum at the ion cyclotron frequency appears as the bursts terminate, suggesting that the mechanism of ion heating involves the dissipation of dynamo fluctuations at ion gyro-orbit scales.

We have used majority-carrier deep-level transient spectroscopy (DLTS) and photocapacitance measurements in a study of lattice defects present in 1.5-μm-thick layers of n-type ${\mathrm{In}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As, 0.045≤x≤0.18, grown by molecular-beam epitaxy (MBE) on n-type GaAs substrates. Each composition shows in the DLTS data an electron trap whose electron parameters agree with those known for the EL2 defect in InGaAs grown by vapor-phase epitaxy, and also the photocapacitance quenching that is characteristic of EL2 traps. Our results demonstrate for the first time that the EL2 defect can be formed in InGaAs during MBE growth, and we deduce its likely mode of formation.

A standard model of glasses is shown to exhibit unexpected and remarkably simple elastic properties. For a sequence of networks of decreasing degree or coordination z, the number of zero-frequency vibrational modes (also called ‘‘degrees of freedom’’) increases as ${\mathit{e}}^{\mathrm{-}\mathit{z}/\mathrm{\zeta }}$. A simple statistical model is given which illuminates this behavior. In addition, the elastic constant ${\mathit{c}}_{44}$ decreases as (z-${\mathit{z}}_0$${)}^{\nu }$; in certain cases other elastic constants also exhibit this behavior. These simple functional relationships appear to hold accurately for all z>${\mathit{z}}_0$, where ${\mathit{z}}_0$ is the critical average degree at which the elastic constants vanish.

To determine the time evolution of the droplet size distribution in the nucleation process, we have made light-scattering measurements on supercooled dilute solutions of poly(methyl methacrylate) in 1-chlorobutane, which showed extremely slow phase separation. The observed scattered intensities were analyzed by the Guinier plot and represented in a scaled form. The time evolution of the mean radius R¯(t), total density N(t), and droplet-size distribution N(R,t) of droplets of minority phase was given by the relations R¯(t)∼t, N(t)∼${\mathit{t}}^{0.6}$, and N(R,t)=N(t)h(R/R¯)/R¯, independent of quench depth and concentration.

The structure of perturbation theory for an interacting two-dimensional Fermi system is analyzed, in the case where singular terms exist in the quasiparticle interactions. These give a hierarchy of singular terms in the one-particle self-energy. The dominant terms are self-consistently summed, to give a quasiparticle pole vanishing as Z(ω)∼(ω/${\mathrm{\omega }}_0$${)}_0^{\mathrm{\rho },\mathrm{\delta }2}$/${\mathrm{ħ}}^2$N(0)${\mathrm{\omega }}_0$ near the Fermi energy (signaling a breakdown of Fermi-liquid theory), and a form for the scattering amplitude which is consistent with the assumed form for the quasiparticle interaction.

We have measured ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ adsorption isotherms on a cesium substrate above and below ${\mathit{T}}_{\lambda }$ using a quartz-microbalance technique. The results show that the cesium surface remains dry until the pressure almost reaches the saturated vapor pressure. At liquid-vapor coexistence, however, the wetting film continuously thickens to more than 30 layers. Below ${\mathit{T}}_{\lambda }$, the film at coexistence is superfluid. Above ${\mathit{T}}_{\lambda }$, we resolve a feature in the isotherm just below saturated vapor pressure which is characteristic of a prewetting transition.

Car-Parinello-like calculations have been used to compute the relaxation of the Al(331) surface, with results that are in remarkable agreement with the low-energy electron-diffraction analysis of Adams and So?renson. Rapid screening of the steps on Al(331) is illustrated by comparing its charge density and relaxations to those of Al(110) and Al(111).

The structure of the clean Pt(111) surface has been studied between 300 K and 0.92${\mathit{T}}_{\mathit{m}}$ (${\mathit{T}}_{\mathit{m}}$=2045 K) via x-ray scattering. The surface is unreconstructed for temperatures less than 0.65${\mathit{T}}_{\mathit{m}}$, but reconstructs at higher temperatures to form a layer isotropically compressed and incommensurate with the underlying bulk (111) planes. A disordered arrangement of discommensurations separates regions with ideal fcc stacking from regions with faulted stacking. With increasing temperature, both the compression of the surface layer and the orientational order of the discommensurations increase.