We find static, self-dual solutions to the SU(N) gauged, nonlinear Schrödinger equation in two spatial dimensions with scalar matter in the adjoint representation. The gauge field is determined dynamically by the Chern-Simons interaction with nonrelativistic scalar matter. The hierarchy is associated with the Toda hierarchy, which can be solved explicitly. The N=2 case reduces to the Liouville equation found by Jackiw and Pi, when looking at the nonlinear Schrödinger equation gauged by U(1).

We show that a pseudo Nambu-Goldstone boson, with a potential of the form V(φ)=${\mathrm{\Lambda }}^4$[1±cos(φ/f)], can naturally give rise to an epoch of inflation in the early Universe. Successful inflation can be achieved if f∼${\mathit{m}}_{\mathrm{Pl}}$ and Λ∼${\mathit{m}}_{\mathrm{GUT}}$. Such mass scales arise in particle-physics models with a gauge group that becomes strongly interacting at a scale ∼Λ, e.g., as can happen in superstring theories. The density fluctuation spectrum is non-scale-invariant, with extra power on large length scales.

A global analysis of the ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{-}}$→hadrons data is presented to extract an effective value for the strong-interaction correction to the quark-parton-model approximation to be used for the Z hadronic width. We obtain ${\mathrm{\Gamma }}_{\mathit{h}}$=1782±17(fit)±15 [electroweak (EW) theory] MeV, and a ratio ${\mathrm{\Gamma }}_{\mathit{h}}$/${\mathrm{\Gamma }}_{\mathit{l}}$=21.32±0.24, in good agreement with the results from the CERN collider LEP, and different from the two-loop QCD predictions, ${\mathrm{\Gamma }}_{\mathit{h}}$=1735±6(${\mathrm{\alpha }}_{\mathit{s}}$)±15(EW theory) MeV and ${\mathrm{\Gamma }}_{\mathit{h}}$/${\mathrm{\Gamma }}_{\mathit{l}}$=20.74±0.12, corresponding to ${\mathrm{\Lambda }}_{\mathrm{MS}}$${\mathrm{¯}}^{\mathrm{}\left(5\right)\mathrm{}}$=${140}_{\mathrm{-}80}^{+100\mathrm{}}$ MeV, where MS¯ denotes the modified minimal-subtraction scheme.

We measured the analyzing power A out to ${\mathit{P}}_{\mathrm{\perp }}^2$=7.1 (GeV/c${)}^2$ with high precision by scattering a 24-GeV/c unpolarized proton beam from the new University of Michigan polarized proton target; the target’s 1-W cooling power allowed a beam intensity of more than 2×${10}^{11}$ protons per pulse. This high beam intensity together with the unexpectedly high average target polarization of about 85% allowed unusually accurate measurements of A at large ${\mathit{P}}_{\mathrm{\perp }}^2$. These precise data confirmed that the one-spin parameter A is nonzero and indeed quite large at high ${\mathit{P}}_{\mathrm{\perp }}^2$; most theoretical models predict that A should go to zero.

The pion-nucleon interaction is investigated in a quark potential model with explicit admixtures of quark-antiquark pairs in the baryon wave functions. Two different approximations of the one-gluon-exchange interaction are studied. One of them reproduces all low-energy data reasonably well.

The relative polarization of positrons emitted in pure Fermi ${(}^{14}$O) and Gamow-Teller ${(}^{10}$C) decays has been measured using a new technique based on time-resolved positronium decay. The result ${\mathit{P}}_{\mathrm{GT}}$/${\mathit{P}}_{\mathrm{F}}$=0.9996±0.0037 provides constraints on possible right-handed and scalar-tensor current admixtures to the weak interaction of -4<ζδ×${10}^4$<7 and ‖(${\mathit{C}}_{\mathit{S}}$/${\mathit{C}}_{\mathit{V}}$)-(${\mathit{C}}_{\mathit{T}}$/${\mathit{C}}_{\mathit{A}}$)‖=(1±9)×${10}^{\mathrm{-}3}$ (90% C.L.), respectively.

New measurements and calculations of near-threshold (0.5–5.0 eV) e-${\mathrm{H}}_2$ vibrational-excitation cross sections challenge previous determinations based on transport analysis. Elastic and ${\mathit{v}}_0$=0→v=1 cross sections measured in a crossed electron-molecular-beam apparatus agree well with values calculated using a vibrational close-coupling theory with a separable represetnation of exchange, particularly at energies below 2.0 eV, but are incompatible with cross sections derived via analysis of electron-swarm transport data.

A strong satellite band is observed in the electron spectra of gaseous benzene and toluene obtained by impact of ${\mathrm{He}}^{\mathrm{*}}$($2^3$S) metastable atoms, although the corresponding band has not been found in ultraviolet and x-ray photoemission spectra. The band is assigned to the lowest-lying satellite ${(}^2$${\mathit{A}}_{2\mathit{y}}$ for benzene) predicted previously by many-body calculations, its position being located for the first time. The mechanism for the band enhancement is discussed on the basis of the autoionization process.

We have measured the circular polarization of photons emitted after electron capture into the ${\mathrm{B}}^{2+}$(1${\mathit{s}}^2$2p) state in ${\mathrm{B}}^{3+}$(1${\mathit{s}}^2$)+He(1${\mathit{s}}^2$) collisions in a planar scattering experiment, using the polarized-photon–scattered-ion coincidence technique. The energy is 1.5–12 keV and scattering angles θ are less than 1.5°. For large impact parameters a strong propensity for orientation is observed, with the sense of electron orbiting in the same direction as the rotation of the internuclear axis being favored by more than a factor of 2 compared to the opposite orientation. This is in qualitative agreement with recent theoretical predictions.

Absolute differential ionization probabilities for small impact parameter ${\mathrm{H}}^{+}$+He collision were measured as a function of the electron energy, electron ejection angle, and final recoil-ion charge state. Good agreement was found between an experimental angular distribution of ejected electrons and results of a coupled-channel calculation in the case of single ionization. In the case of double ionization, significant discrepancies to theoretical predictions are found, indicating a breakdown of the independent electron model. Furthermore, evidence is provided that dynamic correlation effects in the two-electron continuum strongly influence the angular distribution of ejected electrons for double ionization.

We have developed a new method and the necessary numerical procedures to solve the time-dependent Schrödinger equation for an atom in intense laser fields. This method allows us to obtain not only the total ionization rate, but also the emitted photoelectron spectrum. We report nonperturbative calculations at high intensity with extensions of the method to systems including a realistic pulse shape. The influence of the resonant intermediate states is seen in the total ionization rate as well as the photoelectron spectrum, and nonlinear ac Stark shifts are found at higher intensities.

By reducing the collision velocity of Rydberg atoms in resonant energy-transfer collisions, we have observed collisional resonances as narrow as 1 MHz, or collision times as long as 1.0 μs. Restricting the collision to a time less than the natural collision time results in transform broadening of the resonances, allowing us to know when an individual collision begins and ends. The latter point is verified by observing the dependence of the collision line shape on the phase of an oscillating field of frequency equal to the width of the collisional resonance.

We report a novel approach to measure rotational tunneling in condensed phases. High-resolution optical spectroscopic methods are used to unravel the tunneling level structure and to measure the rate of the nuclear-spin conversion. The method is demonstrated in experiments on the rotational motion of methyl groups in a crystal of durene doped with di-methyl-s-tetrazine but it can readily be transposed to other tunneling systems.

High-wave-number modes are eliminated in a band characterized by its width parameter λ in k space. The requisite conditional average is evaluated as an approximation in which coupling effects are neglected to order ${\lambda }^2$, for small λ. A fixed point was found under renormalization-group transformation, which corresponded to the Kolmogorov ‘‘-5/3’’ spectrum with spectral constant α=1.60.

We report experimental observations and computer modeling results of large-scale density and temperature modifications (several km extent, δ${\mathit{T}}_{\mathit{e}}$/${\mathit{T}}_{\mathit{e}0}$∼3, ‖δ${\mathit{n}}_{\mathit{e}}$‖/${\mathit{n}}_{\mathit{e}0}$∼25%) created in a low-density, midlatitude, night-time ionosphere by nonlinear refraction of an hf beam launched from a ground-based antenna. The process consists of the reorientation of the reflection surface parallel to the geomagnetic field lines and results in intense heating.

Although collisional drift waves in a sheared slab configuration are linearly damped, it is found that the corresponding turbulence is self-sustaining if initialized at nonlinear amplitude. The influence of the free-energy source represented by the temperature and density gradients on the turbulent system involving bidirectional spectral energy transfer is responsible for this change of regime. Several important features of tokamak edge fluctuations are reproduced by these single-rational-surface nonlinear dynamics. As a result, drift-wave turbulence must still be considered as an underlying dynamic of anomalous transport in tokamak edges.

Vortices in ${}_{}{}^3{}_{}{}^{}\mathit{A}$ in low magnetic fields (H≤20 mT) have been studied by ultrasonics. A first-order phase change between two vortex types, with dissimilar sound absorption, has been found. The magnetic field at the transition is on the order of the dipolar field ${\mathit{H}}_{\mathit{d}}$. The observed change occurs between continuous vortex textures with different topological charges in the d^ field (where d^ is the magnetic anisotropy vector).

A binary liquid-crystal system possessing a tricritical point in its smectic-A–ferroelectric-smectic-C phase boundary is studied. The electroclinic tilt susceptibility and the spontaneous polarization are measured on both the first-order and the second-order side of the tricritical point. The experimental results are compared with predictions of a simple Landau model Good agreement with mean-field behavior is found.

If an ergodic Hamiltonian is changing slowly in time, its energy shell is an adiabatic invariant: Even though the energy changes, an initial surface of constant energy is mapped into a continuous family of surfaces, each of which is also of constant energy. This observation allows efficient and direct dynamical calculation of the entropy of classical fluids, exemplified here by a simple model of liquid water. The results depend substantially on the form of the ‘‘switching’’ function, suggesting possible improvements in traditional thermodynamic switching processes. Application of a similar adiabaticity to Nosé dynamics allows dynamical computation of differences in the Helmholtz free energy.

The effect of hydrodynamics on growth is studied by numerical simulation of two-dimensional phase separation in a simple shear flow. The simulations are performed with a momentum-conserving lattice-gas model of an immiscible binary fluid. The results reveal that an anisotropic anomaly that was previously observed in experimentally obtained structure functions is due to a shear-induced, smecticlike ordering of the domains.