Adding the contribution of the next higher order of the density parameter to the random-phase approximation (the zeroth-order, noninteracting approximation to the susceptibility) improves the calculation of the linear dielectric function of the jellium model. In this paper, the corresponding results by Holas, Aravind, and Singwi [Phys. Rev. B 20, 4912 (1979)] are picked up to extend the Lindhard-Winther theory of the electronic energy loss in a straightforward manner. As known from static approximations to the local-field correction, the electronic stopping at low ion velocities is enhanced. Above the stopping-power maximum, the first-order dynamic dielectric function delivers a correction of the opposite sign. © 1996 The American Physical Society.

By extending the concept of a photonic lattice (PL), we have studied the one-dimensional multiphotonic lattice (MPL) composed of a sequence of different types of PL’s. Each PL plays the role of either a well or a barrier for the electric field due to the difference of photonic band gaps. As a result, bound states of the electric field appear near the band edges, which are strikingly reminiscent of electrons or holes in semiconductor quantum wells. This analogy is confirmed by studying the Stark localization of electric field in the MPL composed of alternate stacks of well-like and barrierlike PL’s. ©1996 The American Physical Society.

We have studied the effect of above-threshold transitions on the (1+1)-photon resonance-enhanced ionization and autoionization processes. We have shown that the effect of the photoionization decay of the autoionizing (AI) state to the higher continuum becomes dominant when the photoionization width of the AI state is comparable to or larger than the autoionization width to within an order of magnitude, i.e., for the intermediate range of laser intensity. The continuum-continuum coupling and the higher-order transitions become effective only for much higher values of the above-threshold transition strengths, i.e., for much higher values of the laser intensity. © 1996 The American Physical Society.

We propose a scheme of transient laser manipulation and cooling of two-level quantum systems with narrow natural linewidths by a sequence of counterpropagating laser pulses with special frequency chirping. Interaction with a large number of laser pulses within the decay time decreases drastically the cooling time of such systems. © 1996 The American Physical Society.

Equations are derived that express the density matrix of a single mode in terms of the normally ordered moments of the photon annihilation and creation operator and that are convergent for arbitrary radiation fields. The procedure consists of introducing a set of analytic generating functions and applying the method of analytic continuation. © 1996 The American Physical Society.

Optical pumping between ground states of a multilevel atom with low-intensity finite-bandwidth squeezed light is shown to exhibit significant qualitative and quantitative differences in behavior in comparison with optical pumping by standard classical light sources. © 1996 The American Physical Society.

In this paper, the relationship between field and atomic squeezing in the thermal Jaynes-Cummings model with an initially coherent atom is examined. © 1996 The American Physical Society.

It is pointed out that the claim of Duan and Guo [Phys. Rev. A 52, 874 (1995)] based on a reasonable definition of the quantum soliton states in optical fibers, that the superposition of momentum eigenstates with the Gaussian weight function makes the fluctuation of the position operator reduce to the minimum, is not correct. © 1996 The American Physical Society.

Using a quantum-optical setting, we demonstrate local-realism violation for a maximally entangled state of two particles without using inequalities. Our proof can be generalized to all arbitrary entangled states for two particles.

Laser-induced resonant transitions in metastable antiprotonic ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ atoms have been found. The observed transitions at wavelengths 593.388±0.001 nm and at 463.947±0.002 nm have been respectively ascribed to the $(n, l)=(38, 34)\to (37, 33)$ and the (36,33)→(35,32) transitions, showing excellent agreements to 50 ppm with recent predictions of Korobov.

We report a detailed observation and theoretical analysis of the double rotational transition $S_0\mathrm{}\left(0\right)+S_0\mathrm{}\left(0\right)\mathrm{}$ of a molecular pair in liquid hydrogen. The experiment has been performed in a wide density range at constant temperature $T=28\mathrm{}$ K. The density behavior of the integrated intensity has been compared with the results of a theoretical model assuming pairwise additivity of intermolecular potential and polarizability. The calculations have been carried out using quantum-mechanical path-integral Monte Carlo simulations to determine the microscopic structure. The importance of the short-range form of the induced anisotropy is pointed out. A satisfactory agreement is found between theory and experiment.

We report a full theoretical calculation of the rovibrational structure of the ${\mathrm{Na}}_2 0_g^{-}$ state, including hyperfine structure. The purely long-range $0_g^{-}$ state has been observed in the photoassociation spectroscopy of ultracold trapped alkali-metal atoms. For the lighter alkali-metal atoms (Li, Na, and K), the purely long-range states are completely characterized by atomic data since the inner turning point of the potentials are at internuclear separations where exchange interactions are still negligible.

In this Rapid Communication an ab initio approach to the inner-shell charge-transfer process in heavy-ion-solid-target collisions is presented. Unlike the extensively studied ion-gas-target systems heavy-ion-solid-target measurements showed systematic deviations from available theories. These deviations were interpreted as revealing a fundamental difference between collisions with gas and those with solid targets. Within the framework of our relativistic formalism a quantitative description of heavy-ion-solid-target charge-transfer processes is reached, thus laying to rest the old problem of solid-target effects. As an example, the results for Cu on a Ni solid target are discussed.

The Auger resonant Raman effect can be used as a method to eliminate natural lifetime broadening in resonant Auger spectra. We have coupled this method with high-resolution photons from the Advanced Light Source to study angular distributions and decay rates of the $\mathrm{Xe}4d_{\frac{5}{2}}\to 6p$ resonant Auger lines. The angular distribution parameters $\beta$ of almost all possible final ionic $5p^4({}_{}{}^3{}_{}{}^{}P, {}_{}{}^1{}_{}{}^{}D, {}_{}{}^1{}_{}{}^{}S)6p$ states have been determined. Our data, which remove the discrepancy between previous lower-resolution experimental results, are compared to different theoretical results.

We present results on the size, density, chemical potential, and lifetime of a Bose-Einstein condensate as a function of the number of condensate atoms for parameters appropriate to the time-averaged orbiting potential trap in which a Bose condensate of ${}_{}{}^{87}{}_{}{}^{}\mathrm{Rb}$ atoms was recently formed [M. H. Anderson et al., Science 269, 198 (1995)]. These results were obtained by solving the time-independent nonlinear Schrödinger equation with anisotropic harmonic trapping potential. We also find vortex solutions for the trap and the critical rotation frequency required for their formation.

We analyze the three-dimensional dynamic expansion of a weakly interacting Bose-Einstein condensate in a harmonic trap when the spring constants of the confining potential are instantaneously reduced. Our results are compared with experimental observation from a condensate of ${}_{}{}^{87}{}_{}{}^{}\mathrm{Rb}$ atoms.