A method of calculating expectation values and transition moments within the framework of the generalized coupled-cluster (CC) method is described. This approach allows for a direct calculation of first- and second-order static properties, as well as response functions for a many-fermion system. Diagrammatic and algebraic techniques of the preceding paper are used to obtain explicit algebraic formulas for what is called one-particle CC density and transition matrices. From these quantities the ground-state expectation value and transition moments for an arbitrary one-particle operator can be easily computed.

This paper deals with the application of Lie algebraic structure theory to time-dependent quantum systems making use of the Levi-Malcev decomposition of the Lie algebra generated by the Hamiltonian and the Wei-Norman representation of the time-evolution operator. In particular, (coupled) harmonic-oscillator systems are studied. Explicit formulas for expectation values and transition probabilities are derived.

Ionization, and capture and loss contributions to the proton stopping power have been calculated in ${\mathrm{H}}_2$, He, ${\mathrm{N}}_2$, Ne, Ar, and Kr targets over the energy range 1–1000 keV. The model is based on the use of empirical analytical ionization, and electron-capture and electron-loss cross-section formulas. Except for energies less than 10 keV, the calculated stopping powers are in reasonable agreement with the data of Andersen and Ziegler.

A simple model, accounting for multiple-hole configurations, is presented in order to study the relative intensities of observed satellite and diagram x-ray lines following L-shell ionization in the region around Z=50. Since satellites arising from LN double- and LNN triple-hole states generally are embedded within the natural width of the parent diagram lines and the observed satellites are due to LM and/or LMX (X=M,N) multiple-hole states, a clear distinction is drawn among the different multivacancy distributions. Moreover, Coster-Kronig transitions and shakeoff processes, which are responsible for the observed satellite structures, are explicitly taken into account. A new analysis of the L-series x-ray spectra, induced by 2.5-MeV proton bombardment, for elements Z=47–53 has been performed based on the present model. $L_1$-subshell level widths ${\Gamma }_1$, fluorescence yields ${\omega }_1$, partial Coster-Kronig transition rates $f_{13M}$, and shakeoff probabilities $P_M$ have been obtained. Present values are in good agreement with recent measurements. However, they show large disagreement with both theoretical calculations and compiled data due to the overestimated intensity and to the assumed sharp cutoff of the $L_1$-$L_3$$M_4$,5 Coster-Kronig transition rates.

The radiative energy shifts produced by environmental modifications of the electromagnetic vacuum are studied from the point of view of stochastic electrodynamics. The vacuum can be modified by the addition of external radiation or by the introduction of conducting objects that alter the distribution of modes. The general formulas obtained are applied to some simple but representative situations. The present results are shown to coincide with previous quantum calculations, and some conceptual differences between the two approaches are discussed.

The environmental effects on the mass renormalization and on the rate of radiative transitions, produced by the presence of conducting objects that alter the electromagnetic-field structure, are studied from the point of view of stochastic electrodynamics. The mass correction is shown to be a tensor that depends on both position and direction of motion. A fluctuation-dissipation theorem is obtained, which leads to the independence of quantum states from environmental changes; only the radiative corrections are affected by the surroundings. The results obtained are discussed in the light of recent experiments and of earlier quantum theoretical calculations.

A high-altitude nuclear electromagnetic pulse (EMP) with a peak field intensity of 5×${10}^4$ V/m carries momentum that results in a retarding force on the average Compton electron (radiating coherently to produce the waveform) with magnitude near that of the geomagnetic force responsible for the coherent radiation. The retarding force results from a self-field effect. The Compton electron interaction with the self-generated magnetic field due to the other electrons accounts for the momentum density in the propagating wave; interaction with the self-generated electric field accounts for the energy-flux density in the propagating wave. Coherent addition of radiation is also quantitatively modeled.

The neon lines at 5852.48 Å (3s’${[1/2]}_1$-3p’${[1/2]}_0$) and 5881.89 Å (3s${[3/2]}_2$-3p’${[1/2]}_1$) were investigated in the presence of electric fields up to 250 kV/cm. With use of a canal ray populating the absorbing 3s levels in the field area, Doppler-free saturation spectroscopic measurements were performed to determine the small electric shifts. The scalar polarizabilities derived are ${\alpha }_{5852\mathrm{A}\mathit{̊}=142.3\mathrm{}\pm 7.7}$ kHz/(kV/cm${)}^2$ and ${\mathrm{\alpha }}_{5882}$ Å=58.3±4.1 kHz/(kV/cm${)}^2$.

Detailed calculation of cross sections and rate coefficients for electron-impact excitation of Ne-like ions is presented in which contributions of the resonance intermediate states, 2$p^5$$n_t$$l_t$nl with $n_t$≤4, are included, leading to the final states 2$p^5$3$l_f$, where $l_f$=0,1,2. The cascade effect greatly complicates the calculation, as compared with the complementary process, the dielectronic recombination. The present study of the ${\mathrm{Fe}}^{16+}$ ion supplements the earlier work by B. W. Smith et al. [Astrophys. J. 298, 898 (1985)], while the ${\mathrm{Se}}^{24+}$ ion was considered in detail for application to soft x-ray lasers. The resonance-excitation effect reduces substantially the existing discrepancy in the case of Se between the simple ionization-balance model and recent plasma experiments.

The phase-fluctuation correlation between the signal and idler fields in nondegenerate parametric optical amplifiers and oscillators is analyzed. It is shown that close to the threshold pump power, the correlation is sufficient to reduce the phase fluctuations below those of a coherent state. The phase-fluctuation correlation is negative due to the simultaneous phase matching and energy conservation. This restricts the usefulness of the correlation. The pump source’s phase noise will furthermore set a limit to the minimum achievable phase spectral density. The conditions for surpassing the standard quantum limit are elaborated. Finally, applications to coherent optical communication and gravitational wave detection are discussed.

We obtain the time-ordered form of the evolution operator for Hamiltonian linear combinations of the generators of the SU(1,1), SU(2), and h(4) groups. The relevance of the obtained results to physics problems such as the generation of non-Poissonian statistics in laser-plasma scattering and the pulse propagation in free-electron lasers is also briefly discussed.

Pump-probe interactions underlie the physics of four-wave and other wave-mixing effects. We present analytic formulas for probe response in a special category of pump-probe experiments. We consider a two-level system excited by two distinct fields, the stronger field with fixed frequency and the weaker with a tunable frequency. We focus attention on the spectral regions near the Rabi sidebands of the strong field and its various subharmonics. We consider times sufficiently short that relaxation effects can be ignored, but sufficiently long to encompass many cycles of population oscillation between the ground and excited states. Because there is no damping, both fields are in this sense strong, and we report here the time average of the response. Our results are obtained by making a suitable second-order rotating wave approximation and are shown to involve the initial phase relation between the two fields as well as the initial angles of orientation of the two-level system’s Bloch vector. Depending on these initial phase and orientation angles, the absorption line shape may be either positive or negative and either symmetric or antisymmetric.

In this first paper of a series on the quantum theory of nondegenerate multiwave mixing applicable to traveling-wave interaction geometries, we describe our problem formulation. We consider the explicit dynamics of a subset of the field quantization modes interacting with a system of stationary two-level atoms contained in a volume much smaller than the field quantization volume. Because we make the realistic assumption of leaving the remaining infinite set of field modes as a common thermal-field reservoir, the resulting Langevin equations contain extra decay terms due to collective spontaneous emission or super-radiance. We show that all but one of these super-radiance terms are negligible in the following two limits: (a) when the number of atoms in a diffraction volume is small; (b) when the atoms are pumped far off resonance. There is, however, an anomalous decay term which does not appear in a classical model of super-radiance based upon coherently phased atomic dipoles. The magnitude of this anomalous term is neither dependent upon the number of atoms nor on the pump-frequency detuning and may not be negligible at a low pump intensity. Neglecting the super-radiance terms, we then present a general Fourier-expansion solution technique for obtaining the atomic polarization in the presence of any number of field modes. The expansion is shown to be convergent in a commonly occurring situation in which all the strong pump modes are frequency degenerate and the remaining nondegenerate modes are all weak compared to the atomic saturation intensity. In subsequent papers of this series, we will present methods to treat, with some rigor, the spatial propagation of an interacting multimode quantum field and apply these methods to traveling-wave squeezed-state generation experiments.

We report studies of new short-wavelength lasers in xenon at 108.9 nm and krypton at 90.7 nm. The lasers are pumped by photoionization of inner-shell electrons followed by Auger decay into excited states. Experiments include measurement of gain and the lifetimes and quenching of the lasing states, the use of a mirror for multipass gain, and studies of the output pulse duration. Numerical simulations which predict gain and the time evolution of the laser output are compared with experiment.

Large-bandwidth laser light pulses with pure frequency fluctuations have been generated. Chaotic-light pulses from a cavityless dye laser are temporally smoothed by passing them through strongly saturated amplifiers. Since the amplification process does not change the phase of the amplified light, the output radiation has the well-defined phase fluctuations of chaotic light, yet essentially no amplitude fluctuations.

Interesting new aspects of atomic behavior in the presence of strong driving fields appear when the driven atom resides not in free space, but in a region (such as an optical cavity) that displays a frequency-dependent photon-mode density. Under such conditions, it is found that a strong driving field can modify the spontaneous decay properties of an atom, and thereby give rise to interesting new features in the spectrum of strong-field resonance fluorescence. It is also found that a high level of dressed-state polarization can be maintained in a sample of resonantly or nonresonantly driven atoms by appropriate tuning of an enclosing cavity. Furthermore, for appropriate laser and cavity tunings, it is found that the atomic states become highly squeezed. In the course of analyzing these effects, a set of modified Bloch equations is derived that explicitly accounts for the finite response time associated with a frequency-dependent photon-mode density.

A coupled set of equations, one describing the time evolution of the ordinary-mode wave energy and the other describing the time evolution of the electron distribution function, is presented. The wave damping is mainly determined by $T_{?}$, while the radiative equilibrium is mainly an equipartition with $T_{\perp }$. The time rate of change of $T_{\perp }$, $T_{?}$, particle density ($N_0$), and current density ($J_{?}$) are examined for finite-$k_{?}$ electron-cyclotron-resonance heating of plasmas. The effects of collisional broadening and collisional damping are also examined. For blackbody absorbing conditions it is shown that the increase of $T_{\perp }$ with time in electron-cyclotron-resonance heating is exponential and not linear. From the quasilinear theory it is found that the Ohkawa steady-state current drive efficiency criterion is really a consequence of the conservation laws of energy, momentum, particle density, and the collisional relaxation of the current density.

We have made conductivity and permittivity measurements from 5–13 MHz on the microemulsion system toluene–brine–sodium-dodecyl-sulfate–butanol in the region where, by varying the brine salinity, the volume fraction of brine in the microemulsion varies from 0.1 to 0.9 as the system passes from one two-phase region to another via a three-phase region. In the two-phase region at high salinities, where the microemulsion consists of brine droplets dispersed in oil, a percolation transition, identified by a steep rise in the electrical conductivity, and a peak in the permittivity, is observed at brine volume fraction $f_p$=0.130±0.001. This transition, although very close to the boundary between the two-phase and three-phase regions, clearly lies inside the two-phase region. The data also suggest that there is a discontinuity in the conductivity at the phase boundary, and we argue that the microemulsion undergoes a change in structure at the phase boundary.

In this paper I compare the conductivity and permittivity measurements reported in the previous paper near the percolation transition in a microemulsion to (i) the predictions of the Bruggeman theory and suitable extensions of this theory, and (ii) models for percolation in dynamic systems. Consideration of the frequency dependence and also an earlier comparison between conductivity and molecular diffusion data show that the stirred percolation model of M. Laguës [J. Phys. Lett. 40, L331 (1979)] cannot explain the raised conductivity exponent observed below the percolation transition in the microemulsion studied here. The Bruggeman theory predicts most of the features of the conductivity and permittivity near the percolation transition, in particular, the frequency dependence, observed in this microemulsion. G. S. Grest, I. Webman, S. A. Safran, and A. L. R. Bug [Phys. Rev. A 33, 2842 (1986)] have attributed the frequency dependence of the conductivity observed in microemulsions with a spherical-droplet structure to dynamic effects. Dynamic effects have little effect on the frequency dependence of the conductivity in the microemulsion studied here. Although this microemulsion is structurally different from that studied by Grest et al., the analysis presented here provides a critical test of their dynamic percolation model.

We have studied adsorption and wetting on a substrate by oil-water-surfactant mixtures using an adaptation of an Ising lattice-gas model originally proposed by Alexander. The bulk of the study consists of mean-field calculations, guided and aided by zero-temperature analysis, low-temperature expansions, exact solutions (in two dimensions), and Monte Carlo simulations. Depending on the interaction parameters, the presence of the surfactants can either discourage or encourage the adsorption of oil-rich or water-rich films on the substrate. Addition of surfactant can effect desorption of a film either by causing a transition from a wetting to a nonwetting regime or by solubilizing the material of the film in the background fluid.