On the Origin of the Non-Fermi Liquid Behavior of SrRuO_{3}

Motivated by the unusual features observed in the transport properties of the ferromagnetic "bad metal" $SrRuO_{3}$, we construct a model incorporating essential features of the realistic structure of this nearly cubic material. In particular, we show how the $t_{2g}$orbital {\it orientation} in the perfectly cubic structure determines the peculiar structure of the hybridization matrix, and demonstrate how the local non-Fermi liquid features arise when interactions are switched on. we discuss the effect of the slight deviation from the cubic structure (at low-$T$) qualitatively. The model provides a consistent explanation of the features observed recently in the optical response of $SrRuO_{3}$.Comment: 4 pages. Submitted to Physical Review Letter

Research investigation directed toward extending the useful range of the electromagnetic spectrum Progress report, 1 May - 31 Oct. 1968

Microwave frequency probes of ionized helium, rubidium lasers, cesium spectrum, and ruby crystal

Orbital Switching and the First-Order Insulator-Metal Transition in Paramagnetic V_2O_3

The first-order metal-insulator transition (MIT) in paramagnetic $V_{2}O_{3}$ is studied within the ab-initio scheme LDA+DMFT, which merges the local density approximation (LDA) with dynamical mean field theory (DMFT). With a fixed value of the Coulomb $U=6.0 eV$, we show how the abrupt pressure driven MIT is understood in a new picture: pressure-induced decrease of the trigonal distortion within the strong correlation scenario (which is not obtained within LDA). We find good quantitative agreement with $(i)$ switch of the orbital occupation of $(a_{1g},e_{g1}^{\pi}, e_{g2}^{\pi})$ and the spin state S=1 across the MIT, $(ii)$ thermodynamics and $dc$ resistivity, and $(iii)$ the one-electron spectral function, within this new scenario.Comment: 4 pages, 4 figures, submitted to PR

The Frobenius group T13 and the canonical see-saw mechanism applied to neutrino mixing

The compatibility of the Frobenius group T13 with the canonical see-saw mechanism of neutrino mixing is examined. The Standard Model is extended in a minimalist way, by introducing a family symmetry and three right-handed neutrinos. To fit experiments and place constraints on the possibilities, tribimaximal mixing is used as a guideline. The application of both a family symmetry group and the canonical see-saw mechanism naturally generates small neutrino masses. The various possibilities from combining these two models are listed. Enough constraints are produced to narrow down the parameters of the neutrino mass matrix to two. This is therefore a predictive model where neutrino mass eigenvalues and allowed regions for neutrinoless double beta decay are suggested.Comment: Accepted for publication in Physical Review D. 13 page