A framework for extracting the low-energy dynamics of pseudoscalar mesons from QCD at large N is developed and, to leading order in the decoupling of heavy mesons, the pure pseudoscalar theory is calculated truncated to four derivatives. The soliton is found not to be manifestly stabilized by the four derivative terms. Under a plausible assumption about the classical solution for the scalar meson field, a natural realization of the previously proposed topological soliton bag model is obtained.

The interaction of a bound electron with the radiation field produced by the image charges that represent a surrounding cavity produces a shift in its orbital frequency and in its radiative decay time. We calculate the frequency shift and the change in the damping constant for a cyclotron motion at the midpoint of a lossy, cylindrical cavity. The frequency shift can easily be so large as to have important consequences for the University of Washington g-2 measurements.

We report the viscous confinement and cooling of neutral sodium atoms in three dimensions via the radiation pressure of counterpropagating laser beams. These atoms have a density of about ∼${10}^6$ ${\mathrm{cm}}^{\mathrm{-}3}$ and a temperature of ∼240 μK corresponding to a rms velocity of ∼60 cm/sec. This temperature is approximately the quantum limit for this atomic transition. The decay time for half the atoms to escape a ∼0.2${\mathrm{cm}}^3$ confinement volume is ∼0.1 sec.

We suggest that ionic conductors containing a dispersed insulating phase are suitable materials for investigating static and kinetic aspects of percolation. We develop a lattice model for the two-phase mixture with special emphasis on the role of an enhanced interface conductivity. By using two-dimensional Monte Carlo simulations we show that our model correctly describes the distinct conduction properties of those materials, and in addition displays the critical behavior of both random-superconducting and random-resistor networks at two different critical concentrations.

A recent muon catalysis experiment with a low-density D-T target saw a pronounced transient in the appearance of fusion neutrons. We propose that this transient is due to resonant molecular formation at epithermal energies. This effect is calculated, including the contribution of direct (as opposed to dipole) mesomolecule formation. The direct process is the dominant one, but has not previously been considered. The results agree well with experiment.

For the first time a transition from a second- to first-order dipole-dipole interaction (van der Waals to resonance interaction) has been observed in a study of the excited EuSr molecule which dissociates into europium 4${\mathrm{f}}^7$5s6p ${\mathrm{}}^8$${\mathrm{P}}_{9/2}$ and strontium 5${\mathrm{s}}^2$ ${\mathrm{}}^1$${\mathrm{P}}_1$ atoms. The transition was verified by measurement of the wavelength dependence in the quasistatic wings of the cw-laser–excited 4595.3-Å line in Eu broadened by Sr ground-state atoms.

We have measured the magnetic field directly inside a thin, circular, parallel-plate capacitor as it is being charged. We find that this field varies linearly with distance from the axis, as is to be expected if a uniform displacement current flows between the plates. The measured slope of B vs r agrees with predictions to within 5%.

Single-mode and multimode self-pulsing instability leading to chaos is reported in the 12.8-μm emission from a homogeneously broadened ${\mathrm{NH}}_3$ laser, near resonantly pumped by ${\mathrm{CO}}_2$ laser radiation. Occurrence of instabilities on two independent emitting transitions over a wide range of operating conditions, including those for optimum lasing, indicate that this behavior is general for near resonantly enhanced two-photon Raman systems of this type.

The radiative decay of the cyclotron motion of a single electron is significantly inhibited when the electron is located within microwave cavity (formed by the electrodes of a Penning trap) rather than in free space. This is the first observation of such inhibited spontaneous emission and the first use of a promising new system for radiative physics. Implications for precision measurements are mentioned.

We present numerical calculations concerning the growth of a large-scale Gaussian spike riding axially over a Gaussian profile intense laser beam. Incorporation of both self-focusing and depletion of the laser beam leads to a criticality with regard to the spike’s initial relative intensity due to the counteracting behavior of these two effects, thereby determining the net power transfer to the spike and its quasistabilization.

Recharging of the Ohmic-heating transformer of a tokamak by means of lower-hybrid waves is demonstrated experimentally in ASDEX. The results are analyzed on the basis of a simple transformer circuit. A recharging efficiency is defined and found to depend on rf power, plasma density, and plasma resistivity modified by the applied rf power. Up to now, we achieved in our recharging experiments in ASDEX a flux swing of FI${̇}_{\mathrm{OH}\mathrm{Mdt}=0.24\mathrm{}}$ V sec, at an rf power of $P_{\mathrm{RF}}$=690 kW, with a pulse duration of 1 sec, while maintaining a plasma with n${¯}_e$=4×${10}^{12}$ ${\mathrm{cm}}^{\mathrm{-}3}$ and $I_p$=290 kA.

Growth rates and saturation of stimulated Brillouin scattering in a ${\mathrm{CO}}_2$-laser–irradiated plasma are investigated by picosecond Thomson scattering of ruby laser light and backscatter spectroscopy. The temporal growth rates are found to be consistent with theoretical predictions. The ion acoustic waves saturate at a fluctuation amplitude of <20% and subsequently show a modulated temporal behavior, as well as sidebands in the backscatter spectra consistent with saturation by strong ion trapping.

The intensity ratio of the second- to the third-harmonic cyclotron emission, measured by a scanning Fourier-transform spectrometer, is investigated for a wide range of discharge parameters. Dependences of the ratio on electron temperature and density are described by the model of plane-parallel walls. The time evolution of central electron density deduced from the ratio is consistent with multichannel ${\mathrm{CO}}_2$ interferometer data within the estimated experimental error.

We use both analytic modeling and computer simulation to show that large-amplitude hose instability of a beam propagating in a gas-filled conducting drift tube can lead to current enhancement. The calculations are applied to explain the results of several recent experiments.

It is pointed out that a continuous random medium can cause an average advance of the arrival time of a pulse. This advance will occur for unsaturated and partially saturated propagation, but not in full saturation (which corresponds to the discrete scatterer case). The effect, which is associated with Fermat’s principle of least time, can be observed by measuring the difference between intensity-weighted and unweighted average arrival times.

A continuum model for critical phenomena in binary mixtures subjected to long-range passive stirring is analyzed in an ε expansion near d=4 using the renormalization group. The random stirring destabilizes the ${\mathrm{\phi }}^4$ fixed point and a new nonanalytic, O(${\mathrm{\epsilon }}^{1/2}$), stable fixed point appears with nonanalytic ε expansions for the critical exponents. The exponent governing the critical temperature lowering as a function of the stirring Reynolds number is 1.74 in d=3.

We employ a phonon-imaging technique to measure the elastic-wave properties of a discrete lattice. Numerical methods are introduced which predict phonon-focusing patterns from dynamical models of interatomic forces. Three recent lattice-dynamics models show significant differences when compared to phonon-imaging experiments on single-crystal GaAs.

Hydrogen and deuterium have been pressurized under static conditions to 1.47 Mbar, which is higher by a factor of 2 than previously reported static data. Measurements of the vibron indicate an initial increase and then a sharp decrease in frequency at pressures above 0.5 Mbar. At 1.14 Mbar the vibron frequency decreased to the zero-pressure value, and at 1.47 Mbar the frequency of the vibron in hydrogen is 90 ${\mathrm{cm}}^{\mathrm{-}1}$ below the value of the vibrational mode of the isolated molecule. This pronounced softening of the vibron suggests strengthened intermolecular interaction.

It is shown that it is impossible to construct, in any reaction in atomic, nuclear, or particle physics, a null experiment that would unambiguously test the validity of time-reversal invariance independently of dynamical assumptions.

A calculation is outlined and results presented for the electric form factor, measured at two values of the momentum, of the pseudo-Goldstone meson within the staggered formulation of lattice fermions.