For a model stationary flow with hexagonal symmetry, we study the recurrence-time statistics. This model flow has been shown elsewhere to provide a sharp transition from normal to anomalous transport. We show here that this transition from normal to anomalous transport is accompanied by a corresponding change of the recurrence-time statistics from ‘‘normal’’ to ‘‘anomalous.’’ In the anomalous case the distribution of recurrence times has a power tail. Recurrence-time statistics provide a local measurement to make evident the existence of anomalous transport.

The radiative opacity of a near-local thermodynamic equilibrium, open-M-shell Ge plasma has been measured in the region of the 2p-3d and 2p-4d transition arrays, and is compared for the first time with the results of a detailed configuration-accounting calculation which includes an approximate treatment of term widths. The plasma was generated by radiation heating using thermal x radiation from a laser-produced gold plasma. Temperature and density were characterized in experiments which observed the absorption spectra of Al and Mg plasmas and by radiographic measurements of the expansion of the heated foil samples.

Larege growth Rayleigh-Taylor (RT) experiments have been conducted by pulse-shaped radiative acceleration of planar fluorosilicone foils with 50-μm wavelength initial surface perturbations. Foils with large-amplitude initial perturbation quickly enter the nonlinear RT regime, and show little growth. Foils with very-small-amplitude initial perturbations grow exponentially for longer, and show much larger growth factors. From comparisons with two-dimensional computer simulations, we deduce that the observed growth is about 60% of that expected for classical RT growth.

The structure of the Lennard-Jones solid, obtained by molecular-dynamics simulation of crystallization in the supercooled liquid, may be fcc, although the hcp structure is energetically more favorable. This could derive from the cubic symmetry of the fcc lattice, allowing lattice defects that are not possible in the hcp arrangement, but are essential to crystal growth in the simulated liquid. Two crossing stacking faults in a small fcc crystallite can produce nonvanishing, growth-promoting, but stacking-fault-resisting, surface steps.

In situ ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ Mössbauer spectroscopy and x-ray diffraction on ${\mathrm{CaFeO}}_3$ (${\mathrm{Fe}}^4$:${\mathit{t}}_2^3$${\mathit{e}}^1$) under pressure have revealed a first-order high-spin (S=2) to low-spin (S=1) transition near 30 GPa. The spin and structure transition is an laternative manifestation of the electronic instabilities of the σ-bonding Fe-O-⇆${\mathrm{Fe}}^{4\mathrm{-}\mathrm{\delta }}$+${\mathrm{Fe}}^{4+\mathrm{\delta }}$, 0≤δ≤1, occurs at a ${\mathit{T}}_{\mathit{t}}$≊290 K. Such instabilities found at the transition from localized to itinerant ${\mathrm{\sigma }}^{\mathrm{*}}$-band electrons reflect a sensitivity to interactions with the lattice.

The vibron frequencies of ${\mathrm{H}}_2$ and ${\mathrm{D}}_2$ molecules compressed in a Ne matrix have been measured up to 45 GPa in a diamond-anvil cell. This evolution with pressure is seen to be very different from that measured in pure ${\mathrm{H}}_2$ and ${\mathrm{D}}_2$ solids: The vibron frequency displays a strong monotonic increase with pressure. The effect of pressure on the bond length of the isotropic ${\mathrm{H}}_2$ molecules is then extracted from the Raman data with two analyses: A strong decrease is shown.

External boundaries change the fluctuations of a correlated fluid, such as a liquid crystal, thereby causing long-range interactions. We compute how the interaction between two parallel plates is modified by the deformations of one plate. Corrections to the leading interaction decay with the average separation of the plates through an exponent related to the roughness of the boundary. These interactions may also modify the surface fluctuations of thin liquid films.

The two-dimensional growth of Au on Ru(0001) in the submonolayer range has been investigated with scanning tunneling microscopy. Upon deposition at room temperature, highly dendritic islands of one layer thickness grow on large Ru terraces. These irregular island shapes are removed upon annealing to 650 K. The dendritic islands exhibit a fractal character, and a dimensional analysis yields a fractal dimension of 1.72±0.07. The results are in quantitative agreement with a two-dimensional diffusion-limited-aggregation growth mechanism.

The transient absorption spectrum of the self-trapped exciton (STE) localized at an iodine dimer (${\mathrm{I}}_2^{\mathrm{-}\mathrm{-}\mathrm{*}}$) in an iodine-doped KCl crystal (KCl:I) has been investigated at 80 K. The absorption band due to the electronic transition was found around 0.36 eV, and the bands due to the hole transitions around 1.5 to 3.0 eV. The electronic transition band occurred in an extremely lower-energy region than that of the STE in KI or RbI crystals, suggesting the ‘‘on-center’’ configuration of the STE (${\mathrm{I}}_2^{\mathrm{-}\mathrm{-}\mathrm{*}}$) in KCl:I.

We present self-consistent calculations of the electronic shell and supershell structure of sodium clusters with up to N∼1600 atoms at finite temperatures and N∼2800 at zero temperature, employing the spherical jellium model in the local-density approximation and numerically solving the Kohn-Sham equations. The finite temperature of the valence electrons is included by treating them as a canonical subsystem embedded in the heat bath of the ions. We present sensitive quantities for the effects of temperature and self-consistency on the supershell structure, and compare our results with recent experiments and former calculations based on phenomenological mean-field potentials.

Photoabsorption cross sections for ${\mathrm{Ar}}_{\mathit{n}}^{+}$, 3≤n≤80, and ${\mathrm{Xe}}_{\mathit{n}}^{+}$, 3≤n≤30 clusters have been measured. A single absorption maximum in the visible is observed for ${\mathrm{Ar}}_{\mathit{n}}^{+}$, whose redshift with growing n is interpreted as a delocalization of the charge from a trimer to a tetramer ion. For ${\mathrm{Xe}}_3^{+}$, two maxima, and for ${\mathrm{Xe}}_{\mathit{n}}^{+}$, n≥5, three maxima are observed. For n≥5 the positive charge can localize onto either a trimer or a tetramer ion core, both surrounded by neutral atoms. The transition between the two isomers is faster than 10 ns.

We have observed a large enhancement of the spin polarization of electrons extracted from an AlGaAs-GaAs superlattice illuminated by circularly polarized light. A polarization of 71.2 ±1.1(stat)±6.1(sys)% was obtained with a photon wavelength of 802 nm at room temperature. We have also confirmed the removal of the degeneracy between a heavy-hole band and a light-hole band at the Γ point from the laser-wavelength dependence of the polarization.

The energy and wave-vector dispersion of single-particle and collective excitations of the one-dimensional (1D) electron gas in GaAs quantum wires have been determined by resonant inelastic light scattering. In the 1D quantum limit the intrasubband plasmon displays the linear dispersion characteristic of 1D free-electron behavior. Quantitative agreement is found with calculations based on the random-phase approximation. In contrast, 1D intersubband excitations appear as dispersionless and have a negligible shift from the single-particle energy. This mode exhibits the unique Landau damping expected for a 1D system with two occupied subbands.

We study the quantum-Hall liquid to insulator transition in the two-dimensional electron gas, both where the disorder is large, and where it is small so that the insulating state has moderate-range Wigner-crystal order. We use the Chern-Simons–Ginzburg-Landau theory to relate this transition to the transition between quantum-Hall liquids.

Spin polarization and magnetic circular and linear dichroism in photoemission are interpreted in a many-electron approach. The six different ways to orient the three polarizations in the experiment (magnetization, electric vector of the light, and spin of the photoelectron) allow measurement of six different kinds of correlation between the corresponding atomic properties (valance spin, core-hole orbital momentum, and core-hole spin, respectively). This allows us to analyze exchange and hybridization effects and is illustrated for the 2p and 3p photoemission of ferromagnetic Ni metal.

Measurements of the electrical resistivity, magnetoresistance, ac and dc magnetic susceptibility and specific heat on YbBiPt indicate this compound to be a IveryP heavy-electron system. The low-temperature Sommerfeld coefficient of 8 J/${\mathrm{K}}^2$ (mole Yb) is not affected by a phase transition at 0.4 K. We suggest that the heavy-mass state in YbBiPt is unconventional in that it develops from Bloch states in an electronic subsystem with low carrier concentration.

The characteristic time for establishing thermal equilibrium between the lattice and the spin system is 100±80 ps in ferromagnetic gadolinium.

The basic properties of the Hubbard chain are systematically studied in the large-U regime by a path-integral formalism. The bare electron (hole) is shown to be a composite particle of two basic excitations, holon and spinon, together with the nonlocal string fields. Both holon and spinon are described by fermions with gapless spectra. Based on these quasiparticles, various correlation functions are analytically derived.

We study nonequilibrium steady states produced by a competition between anomalous diffusion (random Levy-flight exchanges) and local dynamics satisfying detailed balance for the equilibrium state of either the Ising chain or the spherical model. The phase transitions occurring in these systems are investigated via simulations and an exact solution. The results show that the steady-state properties are dominated by effective long-range interactions decaying with distance as ${\mathit{r}}^{\mathrm{-}\mathit{d}\mathrm{-}\mathrm{\sigma }}$, where d is the spatial dimension while σ is the dimension of the Levy flight.

We have measured the Newtonian gravitational constant using the ocean as an attracting mass and a research submersible as a platform for gravity measurements. Gravitational acceleration was measured along four continuous profiles to depths of 5000 m with a resolution of 0.1 mGal. These data, combined with satellite altimetry, sea surface and seafloor gravity measurements, and seafloor bathymetry, yield an estimate of G=(6.677±0.013)×${10}^{\mathrm{-}11}$ ${\mathrm{m}}^3$ ${\mathrm{s}}^{\mathrm{-}2}$ ${\mathrm{kg}}^{\mathrm{-}1}$; the fractional uncertainty is 2 parts in 1000. Within this accuracy, the submarine value for G is consistent with laboratory determinations.