An interpretation of the photoelectron satellite spectrum of Xe at 33-eV photon energy is proposed. On the basis of an extended analysis of the Xe ii spectrum it is shown that an interpretation in terms of $5\mathit{p}$ satellites can explain the strength of the spectrum relative to the main $5\mathit{s}$ line as well as the occurrence of new satellites at low photon energy.

Degenerate four-wave mixing has been suggested as a possible generation scheme for squeezed-state light. A recent analysis of the quantum effects of probe-conjugate loss in backward degenerate four-wave mixing has shown that such loss puts an absolute limit on the squeezing that can be obtained via this generation scheme. In this Rapid Communication we show that it is the counter-propagating beam geometry of backward degenerate four-wave mixing that makes it ill suited for squeezed-state generation. On the other hand, the nominally copropagating beam geometry of forward degenerate four-wave mixing is shown to alleviate the absolute probe-conjugate loss limit on squeezing.

We have performed an experiment in atomic Yb vapor which provides the first demonstration that complex laser pulse-shape information can be stored in and recalled from the spectral distribution of the population in one terminal level of an inhomogeneously broadened optical transition. The information is stored as a result of interference between two temporally separated laser excitation pulses, one of which possesses a complex temporal structure. It is recalled as a feature of a third-excitation-pulse-induced free-decay signal. Recalled signals up to one percent as intense as the original were observed.

A successive subharmonic modulation cascade of self-sustained relaxation oscillations in an inverse order leading to optical turbulence in detuned lasers with compound-cavity configurations is predicted. A brief experimental result which supports the predicted subharmonic modulation phenomenon is shown. The suppression effect of optical turbulence by external light injection, which is important for practical applications, is demonstrated theoretically.

The critical dynamics in the vicinity of the uniaxial-biaxial phase transition in nematics is investigated. We present arguments that the critical dynamics corresponds to model A—i.e., a nonconserved order parameter not coupled to other relevant variables—although the order parameter $\xi$ is coupled to the velocity and there are many cross-coupling terms between the uniaxial nematic director $\overrightarrow{\mathrm{n}}$ and $\xi$. Therefore, the transport parameters are not expected to show any singularities at the transition, a prediction which can be tested experimentally.

The dielectronic satellite lines from the $1s2l_{a}3l_b$ and $1s3l_{a}3l_b$ doubly excited configurations of lithiumlike ions have been studied experimentally and theoretically under dense-plasma conditions. Good agreement between theory and high spectral-resolution measurements performed in laser-target interactions at 0.53-μm wavelength, ${10}^{14}$ W/${\mathrm{cm}}^2$ laser irradiance show that collisional equilibrium conditions are reached between $n=3\mathrm{}$ singly and doubly excited levels at electron densities greater than ${10}^{22}$ ${\mathrm{cm}}^{-3\mathrm{}}$ in Al and Si.

Algorithmic complexity theory is used to discuss the degree of randomness of the sequence of energy eigenvalues of conservative quantum systems.

Unusual deuterium NMR spectral patterns are reported for a magneto-aligned, smectic-$E$ sample consisting of a binary mixture of 4-$n$-butoxybenzylidene-4′-$n$-octylaniline-2, 3, 5, 6-$d_4$ ($4\mathrm{O}.8-d_4$) and 50 wt.% 4-$n$-octyloxycyanobiphenyl(8OCB). This spectral behavior is consistent with the para axis of the aromatic ring of 4O.8 being perfectly ordered ($S=0.99\mathrm{}\pm 0.01$) in the smectic-$E$ phase. The short axis of the ring is also ordered, however, not perfectly ordered, on the average, and undergoing $\pi$ flips about the para axis on a time scale ≲ ${10}^{-5\mathrm{}}$ sec. There are found to be two possible motional models for the orientational ordering of the short axis of the ring that are consistent with the data: (1) molecular diffusion about the herringbone lattice with angular jumps of 44° between lattice sites, or (2) on-site librational motion with an in-plane order parameter of 0.80 for the degree of order of the short axis. Upon transforming from the smectic-$B$ to the smectic-$E$ phase in this material the degree of order of the para axis of the ring is observed to change continuously.

A description of scaling structures in two-extremum, two-parameter, one-dimensional maps is presented. Examples of systems for which such map models apply are given. In parameter space, subharmonic bifurcation displays an infinite binary tree of features connected to a Cantor set of normal (Feigenbaum) cascades. The cascade limit lines are attached to the tree limits, tricritical points. The scaling behavior in the vicinity of the tricritical points is conveniently described with reference to sets of superstable lines and superstable-orbit-segment lines. The parameter-plane scaling with respect to these line sets is related to the renormalization-group treatment of scaling in function space. Power-law conjugacy is used to provide some physical insight into the nature of the second relevant vector that appears in the theory.

Here we report on the use of the $N^{-1\mathrm{}}$ expansion in studying the time evolution of a nonequilibrium quenched state of a Ginzburg-Landau model in zero and one spatial dimension. Results obtained from the $N^{-1\mathrm{}}$ expansion are compared with those obtained using numerical simulations of the Langevin dynamics. We find that the $N^{-1\mathrm{}}$ approximation provides a useful qualitative picture which for $N\gtrsim 3$ becomes a reasonable quantitative representation.

For a one-dimensional nonlinear string described by the equation $\square \varphi +m^2\varphi +g{\varphi }^3=0\mathrm{}$ we study the transfer of energy from the initially excited low-frequency oscillation modes to the high-frequency modes. To this purpose we give a systematic short-time asymptotic expansion of the trajectories of the singularities of $\varphi \mathrm{}(x,t)\mathrm{}$ in the complex $x$ plane which are nearest to the real axis. The results are checked in the numerical solution. We show that the transfer of energy is characterized by spatial intermittency. Our technique for the determination of the analyticity strip of $\varphi \mathrm{}(x,t)\mathrm{}$ extends to higher-order nonlinearities.

We present the classical and the quantum-mechanical descriptions of surface-state electrons which are perturbed by a periodic force $F\left(t\right)=e\epsilon \Sigma n^{} \delta \mathrm{}(t-T)\mathrm{}$. The numerical results are supported by analytical estimates which indicate that the stochastic behavior which characterizes the classical treatment, and which is manifested by the energy diffusion and ionization rates, is suppressed in the quantum-mechanical treatment.

Nonuniversal behavior in the dynamics of phase separation is discussed. An equation which exhibits a nonuniversal growth rate in a long-time limit is derived relying on the dynamic-scaling assumption. Two contradictory behaviors, a crossover to larger growth rate and a formation of a locked-in structure, are shown to be described by this equation in two limiting cases. The intermittent region lies between regions with these two contradictory behaviors. Two types of intermittent-growth-rate exponents are obtained. One, $a_{I1\mathrm{}}$, is valid at high temperatures, while the other, $a_{I2\mathrm{}}$, is valid at low temperatures. These two exponents are, respectively, $a_{I1\mathrm{}}=w_1{a}_1+w_2{a}_2$, and $a_{I2\mathrm{}}={(\frac{w_1}{a_1}+\frac{w_2}{a_2})}^{-1\mathrm{}}$. Here $w_i \mathrm{}(i=1,2\mathrm{})\mathrm{}$ are the probabilities of finding configuration associated, respectively, with the growth rates $R\propto t^{a_1}$ and $R\propto t^{a_2}$. $a_1$ is the largest exponent due to the curvature-driven force and $a_2$ is the next largest exponent; $a_2=0\mathrm{}$ at zero temperature. Thus, for certain values of system parameters, the intermittent exponent $a_I$ varies from $0 \mathrm{to} a_{I1\mathrm{}}$ as the temperature is increased. Several aspects of the growth rates in parameter space are predicted. They are consistent with numerical simulations and fluid mixtures.

With a force expression valid at optical frequencies, a systematic study of the thrust on an immersed object under light illumination and the associated problem of the momentum residing in a pulse of light is carried out. Depending on the state of the liquid, various explicit results, which include the effects due to fluid pressure, are obtained. Corrections due to weak dispersion are shown to be totally negligible except for a plane wave. Interpretation using the concept of pseudomomentum is found to be useful in some situations but meaningless in others.

In a previous paper [Phys. Rev. A 29, 2186 (1984)], the motion of a particle trapped in a quartic double-well potential, in the presence of a dynamic monochromatic external field, was studied. Renormalization-group techniques were used to determine at what external-field amplitude (for a given frequency) a low-energy particle can be driven over the barrier. In the present paper, we study the effect of a low-frequency field on this system, and we determine the limits of validity of the pendulum approximation which is basic to the use of renormalization-group techniques.

The quantum corrections to the thermodynamic properties of simple molecular fluids have been calculated, with the influence of quadrupole moment, induced dipole moment, anisotropic dispersion, and shape factors taken into account. Expressions are given for the free energy, pressure, entropy, and internal energy, and results are reported for ${\mathrm{D}}_2$ and ${\mathrm{H}}_2$. It may be seen that the rotational contribution to the quantum effect is very small in comparison to the translational contribution, in which the main contribution arises from the central forces.

The theory of infrared and anisotropic Raman spectra of diatomic molecules dissolved in inert solvents is reexamined without any ad hoc factorization of rotational-vibrational correlation functions. The total correlation function is expanded into a series. Its leading term represents the simple product approximation and its higher-order terms the successive corrections. An order-of-magnitude estimation of corrective terms is presented. They prove to be small, in weakly interacting van der Waals solutions at least, and their spectral effects by no means conspicuous.

Previous results concerning the Dirac energies and wave functions in a space of constant positive curvature are used to derive their counterparts in a space of constant negative curvature. In particular, it is shown that, when switching from a spherical closed space to a hyperbolic open space, the sign of the curvature-induced splittings and shifts in the hydrogenic fine-structure spectrum is reversed.

Cross sections for rotationally elastic and inelastic scattering of low-energy positrons by methane molecules are reported in the adiabatic-nuclei-rotation approximation. A model-potential approach is employed, in which an accurate static potential is appended with an ab initio nonparametric polarization potential. The present positron results are compared with the corresponding electron cross sections. There are remarkable differences between the two sets of results for both elastic and inelastic processes.

A close-coupling calculation using a nine-state pseudostate expansion is performed in the intermediate-energy range for a simplified model of electron-hydrogen scattering. The resulting elastic scattering and excitation cross sections exhibit rather narrow structure below pseudothresholds. Except for this narrow structure, the cross sections have converged to the exact results and the $T$-matrix elements have converged to the previously corrected $T$-matrix elements for a smaller basis set.