It is shown that the evolution of the density perturbations during certain eras of substantial entropy generation in the Universe can be described in the scheme of the Kardar-Parizi-Zhang equation. Therefore, the influence on cosmological structure formation by stochastic forces arising from various dissipations can be studied through the universal characteristics of surface growth in d=3+1 dimensions. We identify eras of strong stochastic fluctuations and describe dynamically how these other dissipative sources of noise, besides initial (inflationary) quantum fluctuations, generate seeds of density perturbation with power law spectrum, including the Harrison-Zeldovich spectrum.

We calculate the Isgur-Wise function by measuring the elastic scattering amplitude of a D meson in the quenched approximation on a ${24}^3$×48 lattice at β=6.2, using an O(a)-improved fermion action. Fitting the resulting chirally extrapolated Isgur-Wise function to Stech’s relativistic-oscillator parametrization, we obtain a slope parameter ${\mathrm{\rho }}^2$=1.$2_{\mathrm{-}3}^{+7\mathrm{}}$. We then use this result, in conjunction with heavy-quark symmetry, to extract ${\mathit{V}}_{\mathit{c}\mathit{b}}$ from the measured B¯→${\mathit{D}}^{\mathrm{*}}$lν¯ differential decay width. We find ‖${\mathit{V}}_{\mathit{c}\mathit{b}}$‖ √${\mathrm{\tau }}_{\mathit{B}}$/1.48 ps =0.${038}_{\mathrm{-}2\mathrm{-}3}^{+2+8\mathrm{}}$, where the first error is due to experimental uncertainties, while the second is due to the uncertainty in our lattice determination of ${\mathrm{\rho }}^2$.

The average squared transverse energy of jets in deep-inelastic muon-nucleon scattering is measured as a function of the momentum transfer squared (${\mathit{Q}}^2$), in the range 3<${\mathit{Q}}^2$<25 ${\mathrm{GeV}}^2$. Perturbative QCD predicts that the average squared parton transverse energy will depend upon the strong coupling constant (${\mathrm{\alpha }}_{\mathit{S}}$). Identifying the transverse energy of the jets with those of the corresponding partons, ${\mathrm{\alpha }}_{\mathit{S}}$ is found to vary with ${\mathit{Q}}^2$ as predicted by QCD.

The giant dipole resonance γ decay of ${}_{}{}^{240}{}_{}{}^{}\mathrm{Cf}$ excited to 67 and 93 MeV was measured from the fusion of ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$${+}^{208}$Pb. The γ spectrum and γ-fission angular correlation are analyzed in terms of prefission and postfission γ-ray yields using a stattistical model with nuclear viscosity in the fission process. The results show a strong increase in the prescission γ yield from 67 to 93 MeV. A saddle to scission time ${\mathrm{\tau }}_{\mathrm{s}\mathrm{s}\mathrm{c}=}$30×${10}^{\mathrm{-}21}$ s is extracted from this γ yield, equivalent to a normalized viscosity γ≊5 and full one-body dissipation.

The absorption and fluorescence spectra of an atom driven by a strong, in general, off-resonance external field and coupled to a single cavity mode is investigated. It is shown that for moderate coupling constant the spectral components can become ultrasharp lines whose linewidths are narrower than both the natural linewidth and the cavity decay rate.

We discuss time-dependent spatially localized solutions of the quintic complex Ginzburg-Landau equation applicable near a weakly inverted bifurcation to traveling waves. We find that there are—in addition to the stationary pulses reported previously—stable localized solutions that are periodic, quasiperiodic, or even chaotic in time. An intuitive picture for the stability of these time-dependent localized solutions is presented and the novelty of these phenomena in comparison to localized solutions arising for exactly integrable systems is emphasized.

The behavior of two antiparallel vortices of equal strength, moving in an ideal fluid, is studied numerically. The system is unstable and after a transient period two points of the vortices collide. On their way to the collision the two vortices form a pyramidal structure which is independent of the initial conditions. The connection process tends to follow a universal route for all kinds of initial vortex-antivortex arrangements.

It is suggested that large amplitude turbulence in edge plasmas could originate from core fluctuations propagating to the edge. It is shown that a drift wave launched with ñ/${\mathit{n}}_0$≪1 in a dense region can propagate into a sparse region and amplify, in both a slab and a torus. Propagation is cut off by a large velocity increase, suggesting a simple explanation of the observed correlation between edge shear flows and improved confinement (H modes). Evidence for such radial propagation might be found in asymmetries of fluctuations about the toroidal midplane.

The nonlinear group velocity of a short intense laser pulse propagating in a cold underdense unmagnetized plasma is examined. Analytical expressions for the group velocity are derived. These expressions reduce to the usual ∂ω/∂k form for small amplitude and are verified for arbitrary amplitude using particle in cell simualations on a cyclic mesh. We find that the leading edge of a pulse moves at the linear group velocity and that the phase velocity of the excited wake is found to be less than the group velocity of the pulse. The techniques used can be applied to other waves in a plasma.

We study the relativistic generalizations of two-dimensional Sweet-Parker and Petschek reconnection models in the context of a relativistic pair plasma. The solutions show that if the outflow velocity from the resistive region approaches the relativistic Alfvén speed, the outflow density increase from Lorentz contraction allows a much faster inflow and thus a faster rate of magnetic energy dissipation than in the nonrelativistic regime. We briefly suggest applications of this result.

A Re-Ir dimer-vacancy complex can be formed on an Ir(001) surface when the surface is heated to ∼240 K with a Re atom vapor deposited on it. Above ∼210 K, the geometrical center of this complex can displace by one step of the substrate by an exchange displacement of its Ir atom with a substrate Ir atom. This mechanism confines the movement of the complex to four nearest-neighbor sites of the substrate lattice. Only above ∼235 K can the complex move out of these four sites by a combined hopping-exchange mechanism. Above ∼280 K, the Re-Ir dimer can dissociate. Upon dissociation, the Re atom will combine with the vacancy and self-diffusion of Ir will then occur.

Using the ${}_{}{}^{132}{}_{}{}^{}\mathrm{Cs}$ high-pressure Mössbauer effect technique, we were able for the first time to investigate on a microscopic level the pressure effects on the electronic charge densities and lattice dynamics in metallic cesium. A quantitative analysis of the experimental results reveals direct evidence for a gradual pressure-induced 6s→5d electronic transition in metallic cesium in agreement with band structure calculations. From the pressure-induced change of the Debye-Waller factor at 4.2 K, we obtain a new value of the Debye temperature ${\mathrm{\theta }}_{\mathit{D}}$ for metallic Cs of 64(2) K at p=6 GPa (V/${\mathit{V}}_0$=0.33).

Series for the Wilson functions of an ‘‘environmentally friendly’’ renormalization group are computed to two loops, for an O(N) vector model, in terms of the ‘‘floating coupling,’’ and resummed by the Padé method to yield crossover exponents for finite size and quantum systems. The resulting effective exponents obey all scaling laws, including hyperscaling in terms of an effective dimensionality, ${\mathit{d}}_{\mathrm{eff}}$=4-${\gamma }_{\lambda }$, which represents the crossover in the leading irrelevant operator, and are in excellent agreement with known results.

The chemisorption dynamics of ${\mathrm{O}}_2$ on Ag(110) was studied by molecular beams and high-resolution electron energy-loss spectroscopy by measuring the initial sticking probability ${\mathit{S}}_0$ as a function of the molecular translational energy ${\mathit{E}}_{\mathit{i}}$ and angle of incidence ${\mathrm{\theta }}_{\mathit{i}}$ along 〈001〉 and 〈11¯0〉. $S sub 0— scales as ${\mathit{E}}_{\mathit{i}}$ ${\cos }^{\mathit{n}}$${\mathrm{\theta }}_{\mathit{i}}$ with n=1.1 along 〈001〉 and n=1.6 along 〈11¯0〉. This indicates that parallel momentum has a role in promoting adsorption. The effect is connected to the amplitude of the corrugation seen by the ${\mathrm{O}}_2$ molecule.

Properties of molecular transport in nanometer channels where the molecules move all or most of the time in interaction with the surface are shown to differ significantly from those in macroscopic structures. Apart from strong deviations from ordinary flow in its dependence on channel dimensions and temperature, under nonisothermal conditions a new phenomenon arises by the coupling of the molecular flow to the thermally induced phonon flux in the solid. Special attention is given to the manifestation of these effects in the thermomolecular pressure difference as it is the experimentally most easily accessible quantity.

Whereas on the clean (111) surface Pt grows in a multilayer (3D) mode at 300 and 400 K, preadsorption of an ordered p(2×2) oxygen overlayer leads to a high quality layer-by-layer (2D) growth with the oxygen floating on the film. In contrast to other surfactants oxygen can be completely removed from the film surface at the growth temperature. It is demonstrated that the presence of oxygen reduces the barrier height for the motion of PT adatoms across step edges. This facilitates the interlayer mass transport and thus the layer-by-layer growth.

Measurements of the infrared reflectivity of the Kondo insulator ${\mathrm{Ce}}_3$${\mathrm{Bi}}_4$${\mathrm{Pt}}_3$ are reported. Near room temperature the charge dynamics are comparable to those of a heavy fermion compound in the incoherent regime; however, below 100 K the depletion of the low frequency conductivity singifies the development of a charge gap at low frequency (∼300 ${\mathrm{cm}}^{\mathrm{-}1}$). The temperature dependence of the depleted spectral weight scales with the quenching of the Ce 4f moments, demonstrating that the gap formation is due to the local Kondo coupling of charge carriers to the Ce magnetic moments. The spectral weight which disappears as the gap forms must be displaced to energies much larger than the gap.

The exact relations between the order parameter function of the Anderson transition and the distributions of local densities of states (LDSO) and eigenfunction amplitudes are derived. It is shown that the non-power-like critical behavior obtained previously in the framework of Bethe lattice (BL) models and effective medium approximation is an artifact of the BL structure and is inconsistent with d-dimensional spatial structure at any d<∞. The critical behavior at finite d is power-like with d=∞ playing the role of an upper critical dimension. Near the transition point, the distribution function of LDOS is very broad and asymmetric.

Wave vector selective ac Stark effect of the ${\mathrm{\Gamma }}_1$-biexciton state is clearly observed in the steady state regime. The biexciton line splits into two lines with resonant pumping between ${\mathit{Z}}_3$ exciton polariton and the biexciton state. From the splitting energy, we have obtained the relevant dipole moment of 4.2e Å. Observed energy of the dressed state coincides with the value derived from the model with strict energy and quasimomentum selection rule. This implies that the dressed state is established with the coherent mixing of delocalized Bloch states.

The problem of doping in II-VI semiconductors is examined using an ab initio pseudopotential approach with emphasis on ZnSe, ZnTe, MgSe, and zinc blende MgTe. The n-type doping of ZnTe and MgTe is found to be hindered by the formation of localized DX-like deep donor centers. DX centers are found to be energetically unfavorable in ZnSe and MgSe. The possibility of obtaining large band gap MgZnSeTe semiconductor alloys that can be doped low-resistance n- and p-type is discussed.