Implications of a class of neutrino mass matrices with texture zeros for non-zero θ13\theta_{13}

A class of neutrino mass matrices with texture zeros realizable using the group $Z_3$ within the framework of type (I+II) seesaw mechanism naturally admits a non-zero $\theta_{13}$ and allows for deviations from maximal mixing. The phenomenology of this model is reexamined in the light of recent hints for non-zero $\theta_{13}$.Comment: some references added, version published in Physical Review

Anti-Localisation to Strong Localisation: The Interplay of Magnetic Scattering and Structural Disorder

We study the effect of magnetic scattering on transport in a system with strong structural disorder, using exact finite size calculation of the low frequency optical conductivity. At weak electron-spin coupling spin disorder leads to a decrease in resistivity by weakening the quantum interference precursors to Anderson localisation. However, at strong electron-spin coupling, the double exchange limit, magnetic scattering increases the effective disorder, sharply increasing the resistivity. We illustrate the several unusual transport regimes in this strong disorder problem, identify a re-entrant insulator-metal-insulator transition, and map out the phase diagram at a generic electron density.Comment: 7 pages, EPL style, with 4 embedded figs. To appear in Europhys. Let

Symmetry based parameterizations of the lepton mixing matrix

There are many mixing schemes based upon flavor symmetries that predict a vanishing $\theta_{13}$. These mixing schemes need corrections or modifications to account for recent experimental measurements of non-zero $\theta_{13}$. We propose new parameterizations for the lepton mixing matrix to quantify the minimal modifications needed in these mixing schemes. The parameterizations can be factorized in two parts: $U_{0}(a,b)$ and $R(\theta,\phi)$. The first factor can be viewed as a zeroth order mixing matrix coming from some flavor symmetry. It reproduces the popular mixing schemes based upon flavor symmetries for suitable values of $a$ and $b$. The second factor can be interpreted as a minimal modification to the mixing matrix and is responsible for non zero $\theta_{13}$, non-maximal $\theta_{23}$ and CP violation. We also find the experimentally allowed parameter space for the parameters $a$ and $b$ and compare it with the symmetry based values for these parameters.Comment: 8 pages, 1 figure, version to appear in Physical Review

Combined Effect of Bond- and Potential-Disorder in Half-Doped Manganites

We analyze the effects of both bond- and potential-disorder in the vicinity of a first-order metal insulator transition in a two-band model for manganites using a real-space Monte Carlo method. Our results reveal a novel charge-ordered state coexisting with spin-glass behavior. We provide the basis for understanding the phase diagrams of half-doped manganites, and contrast the effects of bond- and potential-disorder and the combination of both.Comment: 4 pages, 3 figures, published versio