We report a measurement of the lifetime of the metastable 5$d_{3/2}$26$d_{3/2}$, J=0 autoionizing state of barium. We have determined the lifetime to be 190(10) ns.

The cross sections for the production of Ll, Lα, Lβ, and Lγ x rays in the elements Ta, W, Au, Hg, Tl, Pb, Bi, Th, and U by photons of energies 17.781, 25.770, 32.890, and 43.949 keV have been measured, using a standard double-reflection experimental setup. The measured values have been interpreted in terms of the photoionization cross sections, fluorescence yields, Coster-Kronig transition probabilities, and radiative decay rates. A fairly good agreement is found between the experiment and calculations.

We have extended observations of total cancellation of three-photon atomic excitation by internally generated fields due to four-wave mixing. The process was found to occur as predicted in an excitation mode involving two photons of frequency ${\omega }_1$ and one of frequency ${\omega }_2$, plus the generated four-wave-mixing field at frequency 2${\omega }_1$+${\omega }_2$. Experiments were conducted on the 6s state of Xe.

A Glauber-Lachs-type formula is derived for the superposition of squeezed coherent states with thermal light.

Coherent Čerenkov radiation has been investigated previously in the time domain for an infinite path. The present calculations for a finite path length show an effect analogous to diffraction (in the frequency domain) in which radiation fields appear both at Čerenkov angles and at other angles. The latter have previously been named electromagnetic pulse fields.

Hong and Mandel’s concept of higher-order squeezing is applied to higher-harmonic generation (k≥2). The fundamental mode is shown to be intrinsically squeezed to the order k of the process for even k and to the order of k-1 for odd k.

Dipole vortex solutions are obtained for a set of nonlinear equations describing low-frequency electromagnetic turbulence in an inhomogeneous magnetized plasma.

We consider a model based on the Maier and Saupe theory in order to explain the reentrant nematic-isotropic transition observed in lyotropic liquid crystals. By assuming a linear dependence of the micellar shape anisotropy with temperature, we show that it is possible to obtain a reentrant transition.

Lyotropic nematic mesophases doped with different concentrations of ferromagnetic grains are observed in a polarizing microscope. A minimum concentration of the grains is obtained above which a collective behavior of the nematic matrix is observed. The results are discussed in terms of the elastic continuum theory of liquid crystals.

When allowance for the finite orientational fluctuations in the end-to-end separation vector of an ideal Gaussian chain is made, while using a constant-length ensemble, the equation of state is no longer the simple Hooke’s-law expression but contains, in addition, a repulsive force which opposes the tendency of the chain to collapse. The implications of this new equation of state are examined.

A singular-point analysis for a quartic Hamiltonian which depends on a parameter is performed. Moreover, the maximal one-dimensional Lyapunov exponent is calculated numerically. It turns out that if two of the resonances determined by the singular-point analysis become complex, then the maximal one-dimensional Lyapunov exponent is larger than 0.

We study diffusion with a topological bias on random structures having dangling ends whose length L is chosen from a power-law distribution P(L)∼$L^{\mathrm{-}(\alpha +1)}$. We find that the mean-square displacement 〈$x^2$〉 of a random walker on the backbone varies asymptotically as 〈$x^2$〉∼(logt${)}^{2\alpha }$, slower than any power of t, in contrast with 〈x〉∼t, the conventional result for a nonrandom lattice. Our predictions are confirmed by numerical simulations for percolation and for the random comb.

It is explicitly demonstrated with a special model of a measuring arrangement that the result of the measurement is a superposition of states which lie in mutually orthogonal Fock spaces and the final state cannot be distinguished from a mixture. This breaking of the symmetry of the apparatus by the measured object is possible because of Anderson’s infrared catastrophe, occurring in a Fermi gas, which is part of the equipment. The connection to macroscopic quantum phenomena is discussed.

I question the claim made by Barut and Van Huele [Phys. Rev. A 32, 3187 (1985)] that the Lamb shift can be obtained from classical field equations without field quantization.

The relation between the formulations of quantum electrodynamics based on self-energy and the standard perturbative quantum electrodynamics is further elaborated and a simpler model is given.

Henderson [Phys. Rev. A 32, 2336 (1985)] has proposed that the critical exponent for adsorption should be either γ or γ/2, where γ is the (bulk) compressibility exponent. It is shown that both results are artifacts of the mean spherical approximation (MSA) employed by Henderson. The MSA, and closely related closures of the wall-particle Ornstein-Zernike equation, are essentially linear-response approximations which neglect nonlinearities that are crucial in critical adsorption, even at the mean-field level. Our argument is made explicit by re-deriving the correct (Fisher–de Gennes) exponent ν-β and illustrating the failings of linearized treatments. Since the latter also fail to describe complete wetting, their validity is restricted to states well removed from bulk two-phase coexistence.

Despite the deficiencies noted by Evans and Marconi, preceding Comment, and noted earlier by myself, the simple theory of adsorption I proposed [Phys. Rev. A 32, 2336 (1985)] is very successful in many applications and, at the very least, is a remarkably useful description of supercritical absorption.

We have measured the hyperfine mixing of the $6S$ and $7S$ states of cesium using a new high-precision experimental technique. By comparing the diagonal and off-diagonal hyperfine interaction for these states, we find that a single-particle description of the states is accurate to better than 2%.

We present an experimental study which shows that a large fraction (≤ 50%) of thermal Cs atoms are nearly specularly reflected by polished glass surfaces at grazing incidence. This effect is interesting in the context of projects aimed at storing cold alkali-metal atoms in boxes.

Bound excited states of HeH, formed by electron capture in a beam of 6-keV He${\mathrm{H}}^{+}$ ions passing through Cs vapor, were observed to undergo both predissociation and radiative dissociation. Measurement of the kinetic energy spectrum of the H-atom products was facilitated by their conversion to ${\mathrm{H}}^{-}$. Transformation of the laboratory energy spectrum to the 0° and 180° center-of-mass energy release spectra reveals a broad peak at about 8.4 eV, consistent with predissociation from several vibrational levels of the qq$A{}_{}{}^2{}_{}{}^{}\Sigma _{}^{+}{}_{}{}^{}$ state, and a lower peak at about 3.3 eV, resulting from the $B{}_{}{}^2{}_{}{}^{}\Pi \to X{}_{}{}^2{}_{}{}^{}\Sigma _{}^{+}{}_{}{}^{}$ radiative decay recently observed by Möller, Beland, and Zimmerer.