The Brownian motion of an overdamped particle in a fluctuating anharmonic potential is studied via analog simulation with the major aim of determining the steady-state correlation function ${\mathrm{cphi}}_x$(t)≡〈x(0)x(t)${〉}_{\mathrm{ss}}$/〈$x^2$ ${〉}_{\mathrm{ss}}$, x being the space coordinate of the Brownian particle. It is shown that in the intense-noise region ${\mathrm{cphi}}_x$(t) exhibits a damped oscillatory behavior. This is a direct proof of the existence of a noise-induced transition from the overdamped to the inertial regime, on which the theory of our earlier paper [S. Faetti et al., Phys. Rev. A 30, 3252 (1984)] rests. The experimental oscillation frequency is compared with the predictions of statistical linearization.

A simple dynamical model for the intermittent droplet growth is presented. This model is mapped onto the electric networks, and then renormalized. An intermittent kinetic exponent for the droplet growth is obtained. The use of the geometric mean of local kinetic equations gives consistent results with the simple dynamical model.

A longitudinal electrostatic electron plasma wave excited at the difference frequency of two laser beams is shown to be unstable against filamentation instability in a hot collisionless plasma. The relativistic Vlasov equation has been solved to obtain the nonlinear response of electrons. It is noticed that for a considerable power density of the excited electron plasma wave the growth rate of the filamentation instability is quite high.

The interfacial tension of the simple-cubic Ising model near the transition temperature has been calculated with use of an extension of a recently proposed novel Monte Carlo method. Finite-size scaling theory was used to analyze the results and to obtain the surface tension amplitude. Universal ratios involving the surface tension amplitude are evaluated. Previous ambiguities in the theoretical value of the ratio involving the surface tension and specific-heat amplitudes have been clarified.

The conditions for the existence of large-amplitude localized electromagnetic wave pulses in an electron-positron plasma penetrated by a very strong ambient magnetic field are obtained. It is shown that such pulses can exist in pulsar polar magnetospheres.

By means of computer simulation we have calculated the quantum-corrected pair distribution function g(r) of liquid neon up to the term ${ħ}^6$ of the Wigner-Kirkwood series expansion. The agreement between calculation and the experimental data at T≃35 K of De Graaf and Mozer is now, for the first time, satisfactory.

It is shown that the divergence of the pressure at the close-packed volume for the metastable supercooled fluid branch may be less singular than that of a first-order pole—the result of the free-volume theory. Such weaker singularity gives a possible explanation of why the numerical values found for the close-packed volume are always less than Bernal’s random close-packing volume.

A factor of about ${10}^{\mathrm{-}6}$ has been omitted from a key formula of the recent paper of F. A. Franz and A. Sieradzan [Phys. Rev. A 29, 1599 (1984)]. The arguments of the paper are also inconsistent with the principle of detailed balance.

We discuss several points not considered in the preceding Comment on our earlier work, which tend to refute the Comment.

In a previous work [A. B. Weglein, Phys. Rev. A 17, 1810 (1978)], an optimization method to approximate solutions to the time-dependent Schrödinger equation proposed by Chang and Rapp was further developed. We show that, if correct in a mathematical sense, it leads to results which are physically inadequate.

A method for determining optimal approximate solutions of the time-dependent Schrödinger equation was previously presented by Weglein [Phys. Rev. A 17, 1810 (1978)]. Maidagan and Piacentini have written a comment (preceding Comment) on that work. Their conclusion is simply incorrect. We show precisely where the error in their reasoning occurred.

It is shown that contributions from off-energy-shell intermediate states are small for inner-shell electron capture in highly asymmetric ion-atom collisions. We analyze the influence of the on-energy-shell discontinuities of the electron wave function by introducing a cut-off Coulomb potential. We found that these discontinuities, which are mainly responsible for large corrections introduced by the strong-potential Born approximation, do not have physical meaning.

We show that the off-shell factor is essential for a consistent description of electron capture even when effects of screening are incorporated as in the approximate description of Barrachina, Garibotti, and Miraglia.

By considering boundary conditions, it is explained that transient moments of a Fokker-Planck equation may have a long-time decay constant which is smaller than the smallest eigenvalue of the Fokker-Planck operator. For systems sensitive to boundary conditions, the eigenvalues need not be time decay constants.

We show that the derivation of the small-signal gain given by Friedland [Phys. Rev. A 29, 1310 (1984)] actually applies for an incoherent stimulating field with amplitude and phase fluctuations obeying a stationary Gaussian process rather than the standard situation where the stimulating field is assumed to be coherent. The gains are identical in either case; however, the photon statistics are different. We also try to rectify some confusing remarks about the quantum limit of the free-electron laser.

The ranges of ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{131}{}_{}{}^{}\mathrm{Xe}$, ${}_{}{}^{84}{}_{}{}^{}\mathrm{Kr}$, and ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ nuclei stopping in emulsion have been measured at 0.956, 1.22, 1.52, and 0.59 GeV/nucleon, respectively. The ranges are shorter than predicted by the standard Bethe stopping power theory but are consistent with the values calculated by using the higher-order correction terms.

Evidence is presented for a two-step process in ion-atom collisions in which two independent interactions occur in a single encounter. Measurements for 15–200-${\mathrm{MeVS}}^{13+}$+He collisions indicate that uncorrelated projectile K-shell excitation and capture of a target electron occur in a single collision with one target atom. The results are in reasonable qualitative agreement with theoretical predictions of this two-step process.

Preliminary results of experimental and theoretical behavior of a $J_{\mathrm{lower}=1\mathrm{}}$ to $J_{\mathrm{upper}=0\mathrm{}}$ ${(}^7$${\mathrm{F}}_1$${\mathrm{-}}^7$${\mathrm{F}}_0^0$, 570.68 nm in Sm i) transition in a laser-driven optical cavity are reported. Unlike a J=(1/2) to J=(1/2) transition, polarization asymmetry in the switching does not spontaneously appear in the absence of a magnetic field, owing to the effect of Zeeman coherence in the J=1 level. However, with a longitudinal magnetic field, polarization asymmetry in the switching does develop for symmetric driving; we describe this new effect as magnetically induced polarization switching.

The average distances between micelles are measured by x-ray diffraction as a function of temperature in the discotic nematic phase of the lyotropic system comprised of potassium laurate 1-decanol, and ${\mathrm{D}}_2$O. The variations with temperature of the orientational order parameter are found to follow the variations of the shape anisotropy of the micelles, in good agreement with the microscopic models of the Onsager or Flory types.