Resonance energy of the barKNN-piYN system

The resonance energies of strange dibaryons are investigated with the use of the \bar{K}NN-\pi Y N coupled-channels Faddeev equation. It is found that the pole positions of the predicted three-body amplitudes are significantly modified when the three-body coupled-channels dynamics is approximated, as is done in the literature, by the effective two-body \bar{K}N interactions.Comment: 14 pages, 5 figure

Possible spin triplet superconductivity in Nax_xCoO2⋅y_{2}\cdot yH2_{2}0

Combining symmetry based considerations with inputs from available experimental results, we make the case that a novel spin-triplet superconductivity triggered by antiferromagnetic fluctuations may be realized in the newly discovered layered cobaltide Na$_x$CoO$_{2}\cdot y$H$_2$O. In the proposed picture, unaccessable via resonating-valence-bond physics extrapolated from half-filling, the pairing process is similar to that advanced for Sr$_{2}$RuO$_4$, but enjoys a further advantage coming from the hexagonal structure of the Fermi-surface which gives a stronger pairing tendency.Comment: 4 page

Symmetric Linear Backlund Transformation for Discrete BKP and DKP equation

Proper lattices for the discrete BKP and the discrete DKP equaitons are determined. Linear B\"acklund transformation equations for the discrete BKP and the DKP equations are constructed, which possesses the lattice symmetries and generate auto-B\"acklund transformationsComment: 18 pages,3 figure

Higgs condensation as an unwanted curvaton

During inflation in the early universe, the Higgs field continuously acquires long-wave quantum fluctuations. They accumulate to yield a non-vanishing value with an exponentially large correlation length. We study consequences of such Higgs condensations to show that, in inflation models where the universe is reheated through gravitational particle production at the transition to the kination regime, they not only contribute to reheat the universe but also act as a curvaton. Unfortunately, however, for parameters of the Standard Model Higgs field, this curvaton produces density fluctuations too large, so the inflation models followed by a long kination regime are ruled out.Comment: 13 pages; v2, layout adjusted, references adde

On the Magnetic Excitation Spectra of High Tc Cu Oxides up to the Energies far above the Resonance Energy

Magnetic excitation spectra c"(q,w) of YBa2Cu3Oy and La214 systems have been studied. For La1.88Sr0.12CuO4, c"(q,w) have been measured up to ~30 meV and existing data have been analyzed up to the energy w~150 meV by using the phenomenological expression of the generalized magnetic susceptibility c(q,w)=c0(q,w)/{1+J(q)c0(q,w)}, where c0(q,w) is the susceptibility of the electrons without the exchange coupling J(q) among them. In the relatively low energy region up to slightly above the resonance energy Er, it has been reported by the authors' group that the expression can explain characteristics of the q- and w-dependence of the spectra of YBa2Cu3Oy (YBCO or YBCOy). Here, it is also pointed out that the expression can reproduce the rotation of four incommensurate peaks of c"(q,w) within the a*-b* plane about (p/a, p/a) {or so-called (p, p)} point by 45 degree, which occurs as w goes to the energy region far above Er from E below Er. For La2-xSrxCuO4 and La2-xBaxCuO4, agreements between the observed results and the calculations are less satisfactory than for YBCO, indicating that we have to take account of the existence of the "stripes" to consistently explain the observed c"(q,w) of La214 system especially near x=1/8.Comment: 14 pages, 5 figure

Birkhoff strata of the Grassmannian Gr(2)\mathrm{^{(2)}}: Algebraic curves

Algebraic varieties and curves arising in Birkhoff strata of the Sato Grassmannian Gr${^{(2)}}$ are studied. It is shown that the big cell $\Sigma_0$ contains the tower of families of the normal rational curves of all odd orders. Strata $\Sigma_{2n}$, $n=1,2,3,...$ contain hyperelliptic curves of genus $n$ and their coordinate rings. Strata $\Sigma_{2n+1}$, $n=0,1,2,3,...$ contain $(2m+1,2m+3)-$plane curves for $n=2m,2m-1$ $(m \geq 2)$ and $(3,4)$ and $(3,5)$ curves in $\Sigma_3$, $\Sigma_5$ respectively. Curves in the strata $\Sigma_{2n+1}$ have zero genus.Comment: 14 pages, no figures, improved some definitions, typos correcte

The Lick Observatory Supernova Search

We report here the current status of the Lick Observatory Supernova Search (LOSS) with the Katman Automatic Imaging Telescope (KAIT). The progress on both the hardware and the software of the system is described, and we present a list of recent discoveries. LOSS is the world' most successful search engine for nearby supernovae.Comment: 4 pages, 1 figure, Submitted to the proceedings of the 10th Annual October Astrophysics Conference in Maryland on Cosmic Explosion

Stoner gap in the superconducting ferromagnet UGe2

We report the temperature ($T$) dependence of ferromagnetic Bragg peak intensities and dc magnetization of the superconducting ferromagnet UGe2 under pressure ($P$). We have found that the low-$T$ behavior of the uniform magnetization can be explained by a conventional Stoner model. A functional analysis of the data produces the following results: The ferromagnetic state below a critical pressure can be understood as the perfectly polarized state, in which heavy quasiparticles occupy only majority spin bands. A Stoner gap $\Delta(P)$ decreases monotonically with increasing pressure and increases linearly with magnetic field. We show that the present analysis based on the Stoner model is justified by a consistency check, i.e., comparison of density of states at the Fermi energy deduced from the analysis with observed electronic specific heat coeffieients. We also argue the influence of the ferromagnetism on the superconductivity.Comment: 5 pages, 4 figures. to be published in Phys. Rev.

Zero-Field Satellites of a Zero-Bias Anomaly

Spin-orbit (SO) splitting, $\pm \omega_{SO}$, of the electron Fermi surface in two-dimensional systems manifests itself in the interaction-induced corrections to the tunneling density of states, $\nu (\epsilon)$. Namely, in the case of a smooth disorder, it gives rise to the satellites of a zero-bias anomaly at energies $\epsilon=\pm 2\omega_{SO}$. Zeeman splitting, $\pm \omega_{Z}$, in a weak parallel magnetic field causes a narrow {\em plateau} of a width $\delta\epsilon=2\omega_{Z}$ at the top of each sharp satellite peak. As $\omega_{Z}$ exceeds $\omega_{SO}$, the SO satellites cross over to the conventional narrow maxima at $\epsilon = \pm 2\omega_{Z}$ with SO-induced plateaus $\delta\epsilon=2\omega_{SO}$ at the tops.Comment: 7 pages including 2 figure