We study how much gluon shadowing can be perturbatively generated through the modified QCD evolution in heavy nuclei. We model in simultaneously fusions from independent constituents and from the same constituent, both in a proton and in a large loosely bound nucleus of A∼200. In addition to the actual distributions at small x, we study the ratios of the distributions at an initial scale ${\mathit{Q}}_0$=2 GeV, and show that a strong nuclear shadowing can follow from the modified QCD evolution.

We have improved the theoretical triplet ground-state potential of ${}_{}{}^7{}_{}{}^{}\mathrm{Li}_2^{}{}_{}{}^{}$ by means of an inverse perturbation analysis, and find that the diatomic scattering length for ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ atoms in the F=2, ${\mathit{m}}_{\mathit{F}}$=2 ground-state hyperfine level is negative. The consequences of this result for achieving Bose-Einstein condensation in a trapped ultracold ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ gas sample are addressed.

We present the first measurements of rotational distributions for photoionization over extended energy ranges [0≤${\mathit{E}}_{\mathit{k}}$≤200 eV for ${\mathrm{N}}_2$ (2${\mathrm{\sigma }}_{\mathit{u}}^{\mathrm{-}1}$) and of 3≤${\mathit{E}}_{\mathit{k}}$≤125 eV for CO (4${\mathrm{\sigma }}^{\mathrm{-}1}$)]. The ${\mathrm{N}}_2$ and CO results show a strikingly unusual and different energy dependence. Although differences are expected due to the absence of a center of symmetry in CO, detailed calculations reveal that this behavior arises from the presence of Cooper minima in the photoelectron continuum (k${\mathrm{\sigma }}_{\mathit{g}}$) in the case of ${\mathrm{N}}_2$ and from an f-wave shape resonance for 4${\mathrm{\sigma }}^{\mathrm{-}1}$ photoionization in CO.

The first study of very low energy electron attachment to mixed water-ammonia clusters is reported here. A ‘‘magic’’ cluster anion distribution with strong similarities to that of pure water cluster anions is observed. The mixed (${\mathrm{H}}_2$O . . .${\mathrm{NH}}_3$${)}^{\mathrm{-}}$ dimer is created under very specific experimental conditions and its existence is a test of the theory of electron binding by a dipole. This fragile species has a very small electron binding energy as inferred from field detachment experiments.

It is shown that a neutral particle with an electric dipole moment which moves in a magnetic field acquires a topological phase. This phase may be observed in atom or molecular interferometry.

We define paired variables which are the normal modes for electromagnetically induced transparency and use these modes to study the propagation of matched pulses in an absorbing medium.

We have carried out a series of numerical experiments on the propagation of optical pulse pairs in absorbing media under one-photon and two-photon resonant lambda-system conditions. We report the first observation of the spatial evolution of ‘‘dressed-field’’ pulses, the exact analog of the temporal evolution of dressed-atom states.

A vector quantum field theory is employed to study the propagation of an ultracold atomic wave packet in a traveling wave laser beam with a Gaussian intensity profile. The collective dipole-dipole correlation induced by photon exchanges between atoms produces a ‘‘Kerr-type’’ nonlinearity of atomic waves. We show that such an atomic nonlinearity could result in an atomic soliton under appropriate conditions.

Recent studies of universal parametric correlations in quantum chaotic spectra have revealed an astonishing connection to an integrable one-dimensional quantum system. We introduce a continuous matrix model which establishes a direct connection between the quantum Hamiltonian and the exact field theoretic description of spectral correlations. This reveals a common mathematical structure which underlies quantum chaos, matrix models, and a quantum Hamiltonian.

A spatiotemporal system is modeled by a coupled map lattice. Feedback pinnings are used to control chaos of the system by stabilizing a certain unstable reference state. As the pinning distribution is dense enough, the unstable state can be stabilized. If the density is low, the reference state may not be approached asymptotically. In this case, however, the pinnings can still effectively suppress chaos and produce rich spatiotemporal structures. If a solution is locally stable while the transient process to this state is extremely long and chaotic, pinnings of very low density can well control the transient chaos.

We show that the presence of Kramers’ degeneracy plays an important role in determining the localization length of a dynamically localizing quantum chaotic system. Based on the existence of mappings between dynamically localizing systems and tight binding models of disordered strongly localizing solids we conjecture that the localization length is not a universal function of the symmetry class.

A solution to a given equation is structurally stable if it suffers only an infinitesimal change when the equation (not the solution) is perturbed infinitesimally. We have found that structural stability can be used as a velocity selection principle for propagating fronts. We give examples, using numerical and renormalization group methods.

We present a method for computing the topological entropy of one-dimensional maps. As an approximation scheme, the algorithm converges rapidly and provides both upper and lower bounds.

High frequency capillary waves on the surface of dilute aqueous solutions of cetyltrimethylammonium bromide have been studied by quasielastic light scattering. The wave propagation deviates significantly from classical expectation, due to enhanced coupling between the capillary and dilational modes of the surface. At a concentration of 0.04mM the capillary wave behavior clearly demonstrates mixing of these two surface modes. The effects appear to derive from a reduction in the stability of the dilational waves.

A free-electron laser is able to resonate at two different frequencies, both in free space and in a waveguide. The two waves have positive and negative slippage. We describe the nonlinear interaction between the two waves by a set of partial differential equations which in free space do not require the slowly varying envelope approximation (SVEA). In a waveguide a less restrictive SVEA is applied to each wave. By injecting a small signal at the low frequency, a strong signal and bunching are produced at the high frequency. This effect suggests a new method of generating short wavelength radiation.

We consider the cosmological consequences of a spontaneous breaking of non-Abelian discrete symmetries, which may appear as a natural remnant of a continuous symmetry, such as a family symmetry. The result may be a stable domain wall across which an electron would turn into a muon (or ${\nu }_{\mathit{e}}$ into ${\nu }_{\mathrm{\mu }}$) or a flavor analog of an Alice string–domain-wall structure with the same property.

Effects of flow shear on the ion-temperature-gradient-driven instability (ITG mode) is reported. The variable flow shear is created by controllable nonuniform radial electric field. The experimental results show that large flow shear is capable of suppressing the ITG mode but the strength of the required shear is significantly larger than that predicted by most theories.

We have investigated experimentally controlling chaos in a discharge plasma. The power spectra, information dimension, and especially the Lyapunov exponent spectra confirm that a small periodic modulation on the discharge voltage can be effectively used to control chaos in a discharge plasma system.

We introduce a new type of boundary conditions, smooth boundary conditions, for numerical studies of quantum lattice systems. In a number of circumstances, these boundary conditions have substantially smaller finite-size effects than periodic or open boundary conditions. They can be applied to nearly any short-ranged Hamiltonian system in any dimensionality and within almost any type of numerical approach.

Using independent sources one can realize an ‘‘event-ready’’ Bell–Einstein-Podolsky-Rosen experiment in which one can measure directly the probabilities of the various outcomes including nondetection of both particles. Our proposal involves two parametric down-converters. Subcoherence-time monitoring of the idlers provides a noninteractive quantum measurement entangling and preselecting the independent signals without touching them. We give the conditions for high fringe visibility and particle collection efficiency as required for a Bell test.