The complement: a solution to liquid drop finite size effects in phase transitions

The effects of the finite size of a liquid drop undergoing a phase transition are described in terms of the complement, the largest (but mesoscopic) drop representing the liquid in equilibrium with the vapor. Vapor cluster concentrations, pressure, and density from fixed mean density lattice gas (Ising) calculations are explained in terms of the complement generalization of Fisher's model. Accounting for this finite size effect is important for extracting the infinite nuclear matter phase diagram from experimental data.     

Intrinsic ferromagnetism in insulating cobalt doped anatase TiO2

Using complementary experiments we show that the room temperature ferromagnetism observed in anatase Co:TiO(2) films is not carrier mediated, but coexists with the dielectric state. TEM and x-ray absorption spectroscopy reveal a solid solution of Co in anatase, where Co is not metallic but in the +2 state substituting for Ti. Measurements at 300 K yield a M(S) of 1.1 mu(B)/Co atom, while all films are highly insulating. The evidence of intrinsic ferromagnetism in the dielectric ground state of Co:TiO(2) leads to new considerations for the origin of ferromagnetism in transition metal doped oxides.     

Comparison of measurements of phase velocity in human calcaneus to Biot theory

Biot's theory for elastic propagation in porous media has previously been shown to be useful for modeling the dependence of phase velocity on porosity in bovine cancellous bone in vitro. In the present study, Biot's theory is applied to measurements of porosity-dependent phase velocity in 53 human calcanea in vitro. Porosity was measured using microcomputed tomography for some samples (n = 23) and estimated based on bone mineral densitometry for the remaining samples (n = 30). The phase velocity at 500 kHz was measured in a water tank using a through-transmission technique. Biot's theory performed well for the prediction of the dependence of sound speed on porosity. The trend was quasilinear, but both the theory and experiment show similar slight curvature. The root mean square error (RMSE) of predicted versus measured sound speed was 15.8 m/s.     

Phonon-induced resistivity of electron liquids in quantum wires

We study the resistivity of a quantum wire caused by backscattering of electrons by acoustic phonons. In the presence of Coulomb interactions, backscattering is strongly enhanced at low temperatures due to Luttinger liquid effects. Information about the strength of the interactions can be obtained from a measurement of the temperature dependence of the resistivity.     

Enhancement of a 24.77-nm line emitted by the plasma of a boron nitride capillary discharge irradiated by a high-intensity ultrashort laser pulse

Investigations of plasma produced by a boron nitride capillary discharge irradiated with a guided 20-TW Ti: sapphire laser pulse at a peak intensity of 4 x 10(18) W/cm2 are presented. The guided laser radiation in the plasma channel generated He-like ions that, subject to suitable plasma temperature, recombined into Li-like nitrogen ions. Intense radiation at a wavelength of 24.77 nm was observed, indicating possible lasing at the 3d(5/2) - 2p(3/2) transition in Li-like nitrogen.     

Electron transport through a molecular conductor with center-of-mass motion

The linear conductance of a molecular conductor oscillating between two metallic leads is investigated numerically both for Hubbard interacting and noninteracting electrons. The molecule-leads tunneling barriers depend on the molecule displacement from its equilibrium position. The results present an interesting interference which leads to a conductance dip at the electron-hole symmetry point that could be experimentally observable. It is shown that this dip is caused by the destructive interference between the purely electronic and phonon-assisted tunneling channels, which are found to carry opposite phases. When an internal vibrational mode is also active, the electron-hole symmetry is broken but a Fano-like interference is still observed.     

Limit on the electron electric dipole moment in gadolinium-iron garnet

A new method for the detection of the electron electric dipole moment (EDM) using a solid is described. The method involves the measurement of a voltage induced across the solid by the alignment of the sample's magnetic dipoles in an applied magnetic field, H. A first application of the method to GdIG has resulted in a limit on the electron EDM of 5 x 10(-24)e cm, which is a factor of 40 below the limit obtained from the only previous solid-state EDM experiment. The result is limited by the imperfect discrimination of an unexpectedly large voltage that is even upon the reversal of the sample magnetization.     

Statistical measures of the power dropout ratio in semiconductor lasers subject to optical feedback

The influence of the optical feedback ratio and bias current on the mean and the standard deviation of the power dropout ratio of low-frequency fluctuations in external-cavity semiconductor lasers has been studied experimentally. The power dropout ratio was found to increase with increasing optical feedback ratio and to decrease with increasing bias current.     

Measurement of the generalized polarizabilities of the proton in virtual Compton scattering at Q2=0.92 and 1.76 GeV2

We report a virtual Compton scattering study of the proton at low c.m. energies. We have determined the structure functions P(LL)-P(TT)/epsilon and P(LT), and the electric and magnetic generalized polarizabilities (GPs) alpha(E)(Q2) and beta(M)(Q2) at momentum transfer Q(2)=0.92 and 1.76 GeV2. The electric GP shows a strong falloff with Q2, and its global behavior does not follow a simple dipole form. The magnetic GP shows a rise and then a falloff; this can be interpreted as the dominance of a long-distance diamagnetic pion cloud at low Q2, compensated at higher Q2 by a paramagnetic contribution from piN intermediate states.