Comments on "Ohm's Law Survives to the Atomic Scale" by Weber et al

The recent article "Ohm's Law Survives to the Atomic Scale" by Weber et al. [Science 335, 64 (1021)] reveals ohmic transport in quantized P-in-Si wires. We argue that their results have two main deficiencies: (a) the interpretation of conductance data is inadequate for serious systematics; (b) metallic-like structures hold few implications for quantum computing.Comment: 2pp; see http://comments.sciencemag.org/content/10.1126/science.121431

Extended Uniform Ginzburg-Landau Theory for Novel Multiband Superconductors

The recently discovered multiband superconductors have created a new class of novel superconductors. In these materials multiple superconducting gaps arise due to the formation of Cooper pairs on different sheets of the Fermi surfaces. An important feature of these superconductors is the interband couplings, which not only change the individual gap properties, but also create new collective modes. Here we investigate the effect of the interband couplings in the Ginzburg-Landau theory. We produce a general $\tau^{(2n+1)/2}$ expansion ($\tau = 1-T/T_c$) and show that this expansion has unexpected behaviour for $n\geq 2$. This point emphasises the weaker validity of the GL theory for lower temperatures and gives credence to the existence of hidden criticality near the critical temperature of the uncoupled subdominant band.Comment: 10 pages, 4 figure