Everyday makers and expert citizens. Building political not social capital

"Since the elitist myth of the governing class seeks to eliminate the people in connection with the destiny of society, this myth explodes when it is confronted with the fact that without the people, the rulers are as free spirits wandering lonely, dejected and unemployed in an empty world. But without rulers dominating their existence, the people, on the contrary, find that very freedom that calls forth their most creative efforts. Elitism places blind faith in an appropriate governing class. The democratic ideal incorporates a tempered trust in the wisdom and creative genius of the people" (Easton, 1947:418)

Recent revisions to corporate profits: what we know and when we knew it

Initial estimates in the National Income and Product Accounts significantly overstated U.S. corporate profits for the 1998-2000 period. Subsequent revisions reveal that the profitability of the nation's corporate sector in the late 1990s was substantially weaker than "real-time" data indicated. An unexpected surge in employee stock options exercised-and perhaps, in some sectors, firms' inflated statements of profit-may help explain the large downward revisions.Corporate profits ; Stock options ; Statistics ; Economic indicators

Bubble generation in a twisted and bent DNA-like model

The DNA molecule is modeled by a parabola embedded chain with long-range interactions between twisted base pair dipoles. A mechanism for bubble generation is presented and investigated in two different configurations. Using random normally distributed initial conditions to simulate thermal fluctuations, a relationship between bubble generation, twist and curvature is established. An analytical approach supports the numerical results.Comment: 7 pages, 8 figures. Accepted for Phys. Rev. E (in press

Characteristics of the polymer transport in ratchet systems

Molecules with complex internal structure in time-dependent periodic potentials are studied by using short Rubinstein-Duke model polymers as an example. We extend our earlier work on transport in stochastically varying potentials to cover also deterministic potential switching mechanisms, energetic efficiency and non-uniform charge distributions. We also use currents in the non-equilibrium steady state to identify the dominating mechanisms that lead to polymer transportation and analyze the evolution of the macroscopic state (e.g., total and head-to-head lengths) of the polymers. Several numerical methods are used to solve the master equations and nonlinear optimization problems. The dominating transport mechanisms are found via graph optimization methods. The results show that small changes in the molecule structure and the environment variables can lead to large increases of the drift. The drift and the coherence can be amplified by using deterministic flashing potentials and customized polymer charge distributions. Identifying the dominating transport mechanism by graph analysis tools is found to give insight in how the molecule is transported by the ratchet effect.Comment: 35 pages, 17 figures, to appear in Phys. Rev.

Are there nodes in LaFePO, BaFe2_2(AsP)2_2, and KFe2_2As2_2 ?

We reexamined the experimental evidences for the possible existence of the superconducting (SC) gap nodes in the three most suspected Fe-pnictide SC compounds: LaFePO, BaFe$_2$(As$_{0.67}$P$_{0.33}$)$_2$, and KFe$_2$As$_2$. We showed that while the $T$-linear temperature dependence of the penetration depth $\lambda(T)$ of these three compounds indicate extremely clean nodal gap superconductors, the thermal conductivity data $\lim_{T,H \rightarrow 0} \kappa_S (H,T)/T$ unambiguously showed that LaFePO and BaFe$_2$(As$_{0.67}$P$_{0.33}$)$_2$ are extremely dirty, while KFe$_2$As$_2$ can be clean. This apparently conflicting experimental data casts a serious doubt on the nodal gap possibility on LaFePO and BaFe$_2$(As$_{0.67}$P$_{0.33}$)$_2$.Comment: 11 pages, 5 figures A new section "4. Remark on the quantum oscillation (QO) experiments" is adde

Robustness of Quadratic Solitons with Periodic Gain

We address the robustness of quadratic solitons with periodic non-conservative perturbations. We find the evolution equations for guiding-center solitons under conditions for second-harmonic generation in the presence of periodic multi-band loss and gain. Under proper conditions, a robust guiding-center soliton formation is revealed.Comment: 5 pages, 5 figures, submitted to Optics Communicatio

Collapse arrest and soliton stabilization in nonlocal nonlinear media

We investigate the properties of localized waves in systems governed by nonlocal nonlinear Schrodinger type equations. We prove rigorously by bounding the Hamiltonian that nonlocality of the nonlinearity prevents collapse in, e.g., Bose-Einstein condensates and optical Kerr media in all physical dimensions. The nonlocal nonlinear response must be symmetric, but can be of completely arbitrary shape. We use variational techniques to find the soliton solutions and illustrate the stabilizing effect of nonlocality.Comment: 4 pages with 3 figure

Hyperfine Interactions in the Heavy Fermion CeMIn_5 Systems

The CeMIn_5 heavy fermion compounds have attracted enormous interest since their discovery six years ago. These materials exhibit a rich spectrum of unusual correlated electron behavior, and may be an ideal model for the high temperature superconductors. As many of these systems are either antiferromagnets, or lie close to an antiferromagnetic phase boundary, it is crucial to understand the behavior of the dynamic and static magnetism. Since neutron scattering is difficult in these materials, often the primary source of information about the magnetic fluctuations is Nuclear Magnetic Resonance (NMR). Therefore, it is crucial to have a detailed understanding of how the nuclear moments interact with conduction electrons and the local moments present in these systems. Here we present a detailed analysis of the hyperfine coupling based on anisotropic hyperfine coupling tensors between nuclear moments and local moments. Because the couplings are symmetric with respect to bond axes rather than crystal lattice directions, the nuclear sites can experience non-vanishing hyperfine fields even in high symmetry sites.Comment: 15 pages, 5 figure

Tunable Fano effect in parallel-coupled double quantum dot system

With the help of the Green function technique and the equation of motion approach, the electronic transport through a parallel-coupled double quantum dot(DQD) is theoretically studied. Owing to the inter-dot coupling, the bonding and antibonding states of the artificial quantum-dot-molecule may constitute an appropriate basis set. Based on this picture, the Fano interference in the conductance spectra of the DQD system is readily explained. The possibility of manipulating the Fano lineshape in the tunnelling spectra of the DQD system is explored by tuning the dot-lead coupling, the inter-dot coupling, the magnetic flux threading the ring connecting dots and leads, and the flux difference between two sub-rings. It has been found that by making use of various tuning, the direction of the asymmetric tail of Fano lineshape may be flipped by external fields, and the continuous conductance spectra may be magnetically manipulated with lineshape retained. More importantly, by adjusting the magnetic flux, the function of two molecular states can be exchanged, giving rise to a swap effect, which might play a role as a qubit in the quantum computation.Comment: 9 pages, 10 figure