We investigate the dynamics of monopole annihilation by the Langacker-Pi mechanism. We find that considerations of causality, flux-tube energetics, and the friction from Aharonov-Bohm scattering suggest that the monopole annihilation is most efficient if electromagnetism is spontaneously broken at the lowest temperature (${\mathit{T}}_{\mathrm{em}}$≊${10}^7$ GeV) consistent with not having the monopoles dominate the energy density of the Universe.

The SU(2) glueball wave functions 〈0‖${\mathit{A}}_{\mathrm{\mu }}^{\mathrm{°}}$(x)${\mathit{A}}_{\nu }$(y)‖G〉 are measured on the lattice in the Coulomb gauge, using a source method. It is found that the tensor glueball is about 4 times as large as the scalar glueball. Phenomenological implications for identifying glueballs are discussed.

High-energy γ rays have been measured in coincidence with heavy fragents in deeply inelastic reactions of ${}_{}{}^{136}{}_{}{}^{}\mathrm{Xe}$${+}^{48}$Ti at 18.5 MeV/nucleon. The giant dipole resonance (GDR) strength function is deduced from an analysis of the photon spectra within the statistical model. The GDR width Γ is studied as a function of the fragment excitation energy ${\mathit{E}}^{\mathrm{*}}$. A saturation at about Γ=10 MeV is observed for ${\mathit{E}}^{\mathrm{*}}$/A≥1.0 MeV/nucleon.

We have perfromed high-precision measurements of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ charge and magnetic form factors up to ${\mathit{Q}}^2$=1 (GeV/c${)}^2$. These measurements combined with previous data on ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^3{}_{}{}^{}\mathrm{H}$ allow us to separate the three-nucleon isospin charge and magnetic form factors up to ${\mathit{Q}}^2$=1 (GeV/c${)}^2$. A large discrepancy between experiment and theory occurs for the T=1 charge form factor.

We report on a new method to perform rf-resonance spectroscopy of stable terms in atoms and ions. Fast ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}_{}^{+}{}_{}{}^{}$ ions are scattered under grazing incidence from a flat surface, where stable atomic terms are populated preferentially and polarized with respect to their orbital angular momenta and nuclear spins. By a modification of this polarization via magnetic dipole transitions induced by a resonant rf field, we have measured the hf structures of most stable terms in ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ i,ii,iii and deduce from our data the nuclear electric quadrupole moment of ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ with improved precision: Q${(}^{14}$N)=20.0±0.2 mb.

By use of a longitudinal Stern-Gerlach polarization atomic device, we have demonstrated the manifestation of a topological phase for a beam of ${\mathrm{H}}^{\mathrm{*}}$(2s) atoms traveling through a conical magnetic field configuration.

We have obtained the first measurement of electron impact excitation cross sections as a function of energy for a highly charged ion. Collisional excitation cross sections to four n=2 levels of He-like titanium were measured from threshold to 1.7 times threshold. The data conform well to established theory, especially for direct excitation; however, significant differences are found with predicted contributions from resonance excitation and in the treatment of radiative cascades. The latter changes plasma temperatures inferred from titanium Kα line intensities by as much as a factor of 2.

Atomistic simulations of a strong shock wave in a hard-sphere gas are analyzed in terms of thermodynamic forces and fluxes. Evidence is provided that the Burnett corrections to the heat flux significantly improve the agreement with the computed values over the Navier-Stokes predictions in the shock-front region.

The hydrodynamics of polymer solutions is modeled using a newly developed, thermodynamically consistent, generalized bracket formulation. This continuum thermodynamic development clarifies the connection between the physical assumptions introduced in previous models by Helfand and Fredrickson, Onuki, Doi, and Milner and the final governing equations. A quantitative description of the coupling between elastic stresses and concentration changes as well as the modeling of interphases is provided. The resulting equations describe the same phenomenology as the previous works; however, they are quantitatively different.

Motivated by space and laboratory applications, a theory is presented for ions trapped by a charged dust grain in a plasma. The grain’s attractive Debye sphere confines ions after a collision. They shield the grain’s considerable electric charge from external fields. Their number ${\mathit{N}}_{\mathrm{trap}}$ is determined by a balance of the capture and loss rates. At steady state, ${\mathit{N}}_{\mathrm{trap}}$ is independent of the collisional mean free path and increases with the plasma ion density. Because of the density dependence, trapping is significant in laboratory plasmas but not in comparatively less dense space plasmas.

Three-wave nonlinear coupling of spatial Fourier modes is measured in the MST reversed field pinch by applying bispectral analysis to magnetic fluctuations measured at the plasma edge at 64 toroidal locations and 16 poloidal locations, permitting observation of coupling over 8 polodial modes and 32 toroidal modes. Comparison to bispectra predicted by resistive MHD computation indicates reasonably good agreement. However, during the crash phase of the sawtooth oscillation the nonlinear coupling is strongly enhanced, concomitant with a broadened (presumably nonlinearly generated) k spectrum.

We report a study of upshifted and downshifted Raman backscattered light obtained from two different plasma configurations using a 0.53-μm laser pump. The results provide strong evidence of coupling between plasma waves generated by stimulated Raman scattering and ion waves caused by, or facilitating, stimulated Brillouin scattering.

Efficient direct heating of electrons by fast waves has been observed on the DIII-D tokamak. The measured fast-wave heating efficiency was independent of magnetic field, in contrast to the strong inverse magnetic field scaling predicted by the theory of single-pass damping, indicating multiple-pass absorption. The central heating of electrons by the fast waves had a strong dependence on the target eelctron temperature. H-mode plasmas were obtained with fast-wave heating alone for the first time in the direct electron heating regime.

An imaging technique for reconstructing the projected potential of crystals using high-resolution electron holography is developed. This tecnique is used to observe the projected potential of InP along the 〈001〉 direction, to measure the thickness of InP crystals, and to identify In and P atom columns from a high-resolution electron hologram.

The solid-liquid transitions in argon clusters of medium size (N>55) are studied by molecular dynamics simulations on a cluster of 79 atoms. Over an intermediate range of total energy, the cluster exhibits a ‘‘dynamical coexistence’’ of solid and liquid states, in which the cluster fluctuates between solid and liquid states. We propose that for medium-sized clusters, the existence of two types of structures, low-energy solid and high-energy liquid structures, leads to the dynamical coexistence. We predict that the dynamical coexistence is a finite-size effect of a bulk melting transition.

The structure of frustrated smectic phases exhibited by binary mixtures of 4-n-octyloxyphenyl-4’-cyanobenzoyloxybenzoate (DB8OCN) and 4-n-octyloxybenzoate-4’-cyanoazobenzene (8OBCAB) have been studied by high-resolution x-ray diffraction. This system was previously reported to exhibit three incommensurate smectic-A phases. These incommensurate smectic ${\mathit{A}}_{\mathit{i}1}$,${\mathit{A}}_{\mathit{i}2}$, and the soliton ${\mathit{A}}_{\mathit{i}\mathit{s}}$ phases are found to be coexistences of ${\mathit{A}}_{\mathit{d}}$ and ${\mathit{A}}_1$;${\mathit{A}}_{\mathit{d}}$ and ${\mathit{A}}_2$; and ${\mathit{A}}_{\mathit{d}}$,${\mathit{A}}_1$, and ${\mathit{A}}_2$ phases, respectively. As of now, there are no known incommensurate smectic-A phases.

By the use of energy-dispersive x-ray diffraction with synchrotron radiation, pressure-induced structural phase transitions and equations of state were studied on Se in the extended pressure range up to 129 GPa. In contrast to a previous study on Se to 50 GPa, the higher resolution with synchrotron radiation in the present study allowed for an unambiguous identification of the structure for Se-IV as rhombohedral (β-Po type) with one atom in the rhombohedral unit cell, and thus, a close similarity to Te under pressure and Po at higher temperatures is reestablished.

We present a rigorous theoretical treatment which, in agreement with recent experiments, supports the formation of the ordered c(2×2) phase of the CuPd surface alloy on the Cu(001) substrate, and does not support the formation of an ordered overlayer of only Pd atoms on such a substrate. Based on ab initio electronic structure of random CuPd and Pd-vacancy overlayers, we study their stability against ordering using the generalized perturbation method adapted to strongly inhomogeneous systems. The approach, the first of its kind, is general and can be applied to other metal-on-metal overlayers.

A new systematic theory for the dynamics of phase separation of quenched binary systems in a metastable state is presented. Not only the kinetic equation for the single-droplet size distribution function but also the linear equation with the source term for the dynamic structure function are derived from a unifying point of view. Three characteristic stages with two crossovers in time exponents are shown to exist after the nucleation stage. The dynamical scaling behavior and the time exponents are thus explored explicitly.

A new formulation of the modified weighted density approximation of inhomogeneous classical fluids is presented which is exact to third order in the functional expansion of the excess free energy but includes, approximately, correlations to all orders. It requires as input the pair and triplet structure of the uniform liquid, and when applied to the one-component plasma yields results which are in good agreement with simulation data.