Langevin-type finite-temperature simulations show that soliton mobility in hydrogen-bonded chains is a nonmonotonic function of temperature. In the temperature range of 170–240 K, soliton mobility initially increases, reaches a maximum at approximately 190 K, subsequently decreases to a minimum at approximately 210 K, and then increases again. This behavior is in qualitative agreement with experimental data for ice crystals in the same temperature range.

It is found that the layer normal of a chiral smectic-A liquid crystal is tilted away from an easy axis created by a unidirectional rubbing. The alignment angle of the tilted layer normal with respect to the easy axis approaches about 18°, which is substantially larger than what has been previously observed. This larger deviation cannot be described in terms of the surface electronic effect, and an alternative mechanism is proposed on the basis of molecular chirality and the degree of smectic ordering at the surface.

The intermediate phase of the intermetallic alloy CsPb is shown to be a plastic crystal characterized by jump reorientations of ${\mathrm{Cs}}_4$${\mathrm{Pb}}_4$ structural units. The wave-vector variation of elastic and quasielastic intensities is well reproduced by a simple model of independent structural units jumping between the four orientations observed in the crystal at room temperature. This represents the first observation of a plastic-crystal phase in a metal alloy.

The free decay of the quantized vortex tangle in a channel is observed to occur in two distinct stages, an initial rapid decay in agreement with current theory, followed by a regime of anomalously slow decay. It is argued that the second stage represents a state of coupled turbulence involving not only the quantized vortex tangle, but also macroscopic random motion of the normal and superfluid fields.

It is shown that in insulators heavy particles should delocalize into Bloch waves up to quite high temperatures. The dissipative coupling to phonons can be treated in a one-phonon scattering approximation, giving a ${\mathit{T}}^{\mathrm{-}3}$ dependence to the long-time diffusion of the particle. This theory apparently agrees with recent muonium experiments in KCl.

This letter reports the Hall mobility of electrons injected into liquid xenon whose thermodynamic state is varied along the liquid-vapor coexistence line from the triple point to 275 K. Contrary to what would be expected from transport theory, when ${\mathrm{\omega }}_{\mathit{c}}$τ<1, the Hall angle is not a linear function of the magnetic field. This is particularly important near the mobility maximum and is interpreted as arising from interference effects. Their importance is a consequence of the fact that at the mobility maximum, the electron-phonon interaction is zero while elastic scattering by large density fluctuations persists.

The R${\mathrm{Mn}}_2$ compounds are characterized by an instability of the Mn moment in a highly frustrated crystallographic structure. Although quite general, this problem has not yet been treated. A model derived from the Hubbard Hamiltonian is proposed. It accounts for the new physics observed: complex ordered phases where magnetic and nonmagnetic sites coexist and unusual dependence on external parameters.

We have determined the critical exponent which characterizes the approach of the zero-temperature conductivity to the insulating phase from measurements down to 60 mK of the resistivity of a series of just-metallic uncompensated p-type Si:B samples with dopant concentrations near the critical concentration for the metal-insulator transition. Our results indicate a critical exponent for Si:B of 0.${65}_{\mathrm{-}0.14}^{+0.05\mathrm{}}$, which is close to the ‘‘anomalous’’ values near 1/2 found for the uncompensated n-type silicon-based semiconductors Si:P, Si:As, and Si:Sb. This implies that, despite strong spin-orbit scattering, Si:B belongs to the same universality class as other silicon-based systems.

Conduction in the ON state of amorphous-silicon memory devices is constrained to a narrow conducting filament. We present experimental evidence to show that the memory ON state is associated with quantized electron transport which is presumably related to quantum confinement effects in the small conducting filament. Current-voltage characteristics of typical ON states exhibit discrete steps which correspond to quantized resistance states and the steps split appropriately in a magnetic field. An especially notable feature is that the quantization can be observed at relatively high temperatures (up to ∼190 K).

We report on the observation of interference between intrinsic voltage oscillations generated by sliding spin-density waves and an externally applied ac current in (TMTSF${)}_2$${\mathrm{AsF}}_6$ (TMTSF denotes tetramethyltetraselenafulvalene).

Transport measurements of a Coulomb island, a semiconductor dot small enough that Coulomb interactions dominate transport are presented. At moderate magnetic fields (B=2–4 T) the amplitude and position of the Coulomb-regulated conductance peaks show distinct periodic structure as a function of B. This structure is shown to result from the B dependence of the quantized single-particle energy states on the island. Analysis of successive peaks is used to map out the single-particle level spectrum of the island as a function of B.

High-resolution low-energy (1–14 eV) electron scattering from a multilayer solid film of Ar is reported for various energy losses and angles of incidence. We show that the conduction-band density of states of solid Ar is revealed by the variation with incident electron energy of the scattered electron intensity arising from multiple scattering on phonons.

When a radio-frequency current is passed through a paramagnetic Mössbauer absorber containing ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$, sidebands are generated on the 14.4-keV transition at ${\mathrm{\omega }}_{\gamma }$±2nω, where n=1,2,..., and ω is the applied frequency. The new aspect is that only sidebands of even orders appear. These sidebands are shown to be the result of thermomechanical oscillations induced by the rf current.

A modified Young’s double-slit experiment is realized for electrons in a high-mobility two-dimensional electron gas (2DEG). The observed quantum interference is employed to study dephasing by electron-electron interaction on length scales shorter than the elastic mean free path. It is found that the measured phase-breaking length agrees very well with theoretical calculations of the e-e mean free path in an ideal 2DEG. In contrast to the diffusive regime, dephasing occurs via e-e scattering events with an energy exchange on the order of the carrier excess energy.

We study analytically the irreversible reaction A+B→0 under laminar stirring, for equal overall particle concentrations. In contrast to the usually found algebraic decays, here the reactant concentrations display exponential patterns, which stem from the mixing kinetics. The crossover from this short-time behavior to the classical kinetic law in a fully mixed system is also investigated. Furthermore, disorder effects are fundamental, since for strictly regular patterns the short-time decay shows an exponentially exponential time dependence.

We point out a new class of level statistics where the level-spacing distribution follows an inverse power law p(s)∼${\mathit{s}}^{\mathrm{-}\mathrm{\beta }}$, with β=3/2. It is characteristic of level clustering rather than level repulsion and appears to be universal for systems exhibiting unbounded quantum diffusion on 1D lattices. A relaxation of this class is met in a model of Bloch electorns in a magnetic field, where we find a purely diffusive spread of wave packets without the quantum limitations known from chaotic systems like the kicked rotator.

Previous calculations of the emissivity of a plasma due to the decay of transverse photons and plasmons into neutrino pairs have used dispersion relations that are inaccurate at relativistic temperatures or densities. In the high-temperature limit, the use of the current ultrarelativistic dispersion relations increases the emissivity by a factor of 3.185. This may have a significant effect on the initial cooling rate for the core of a neutron star.

We study a new type of self-gravitating object, described by a soliton solution to the coupled system of the Einstein equation and a matter field equation. The solution describing the self-gravitating object is not static but, instead, is periodic, with both the spacetime geometry and the matter field oscillating in time. In particular, we show that a system described by a real scalar field ${\mathit{g}}^{\mathrm{\mu }\nu }$${\mathrm{\phi }}_{;\mathrm{\mu }\nu }$-${\mathit{m}}^2$φ=0 admits such a solution, which is stable under perturbations. The existence of such objects could have important implications for astrophysics and cosmology.

The gauge dependence of matrix elements of the Chern-Simons current ${\mathit{K}}^{\mathrm{\mu }}$ can be computed exactly in the (1+1)-dimensional Schwinger model. The matrix elements are gauge dependent even in the forward direction, i.e., when the momentum transfer vanishes. The Kogut-Susskind dipole mechanism is derived using functional-integral methods.

A method is given which leads to a wide class of models with strong CP invariance. These models contain a spontaneously broken U(1) symmetry. If this symmetry were global, its breaking would lead to a massless scalar. Because the U(1) is anomaly free, it can be gauged, leading by the Higgs mechanism to a massive gauge boson, the aspon, which might be detectable.