Antiferro-quadrupole state of orbital-degenerate Kondo lattice model with f^2 configuration

To clarify a key role of $f$ orbitals in the emergence of antiferro-quadrupole structure in PrPb$_{3}$, we investigate the ground-state property of an orbital-degenerate Kondo lattice model by numerical diagonalization techniques. In PrPb$_{3}$, Pr$^{3+}$ has a $4f^{2}$ configuration and the crystalline-electric-field ground state is a non-Kramers doublet $\Gamma_{3}$. In a $j$-$j$ coupling scheme, the $\Gamma_{3}$ state is described by two local singlets, each of which consists of two $f$ electrons with one in $\Gamma_{7}$ and another in $\Gamma_{8}$ orbitals. Since in a cubic structure, $\Gamma_{7}$ has localized nature, while $\Gamma_{8}$ orbitals are rather itinerant, we propose the orbital-degenerate Kondo lattice model for an effective Hamiltonian of PrPb$_{3}$. We show that an antiferro-orbital state is favored by the so-called double-exchange mechanism which is characteristic of multi-orbital systems.Comment: 3 pages, 3 figures, Proceedings of Skutterudite2007 (September 26-30, 2007, Kobe

Eosinophilia in patients infected with the human immunodeficiency virus

The prevalence and significance of peripheral blood eosinophilia in patients infected with the human immunodeficiency virus (HIV) were evaluated. Fifteen of 119 consecutive patients had absolute eosinophil counts of > 450/mm3. During a mean follow-up period of 419 days eosinophilia could be identified as secondary to a parasitic infection in only one patient. Correlation with disease stage showed a higher rate of advanced disease in patients with absolute eosinophilia. In a multivariate regression analysis, only low CD4+ cell counts, not the CDC disease stage or the use of antiretroviral therapy or primary prophylaxis, contributed significantly to the prevalence of eosinophilia. It is concluded that expen-sive laboratory investigations in asymptomatic patients with advanced-stage HIV disease are neither necessary nor cost effectiv

Equation of motion for a domain wall coupled to gravitational field

The equation of motion for a domain wall coupled to gravitational field is derived from the Nambu-Goto action. The domain wall is treated as a source of gravitational field. The perturbed equation is also obtained with gravitational back reaction on the wall motion taken into account. For general spherically symmetric background case, the equation is expressed in terms of the gauge-invariant variables.Comment: 13 pages, latex, no figures, uses REVTe

SO(10) Cosmic Strings and SU(3) Color Cheshire Charge

Certain cosmic strings that occur in GUT models such as $SO(10)$ can carry a magnetic flux which acts nontrivially on objects carrying $SU(3)_{color}$ quantum numbers. We show that such strings are non-Abelian Alice strings carrying nonlocalizable colored ``Cheshire" charge. We examine claims made in the literature that $SO(10)$ strings can have a long-range, topological Aharonov-Bohm interaction that turns quarks into leptons, and observe that such a process is impossible. We also discuss flux-flux scattering using a multi-sheeted formalism.Comment: 37 Pages, 8 Figures (available upon request) phyzzx, iassns-hep-93-6, itp-sb-93-6

Upper Limit on the molecular resonance strengths in the 12{}^{12}C+12{}^{12}C fusion reaction

Carbon burning is a crucial process for a number of important astrophysical scenarios. The lowest measured energy is around E$_{\rm c.m.}$=2.1 MeV, only partially overlapping with the energy range of astrophysical interest. The currently adopted reaction rates are based on an extrapolation which is highly uncertain because of potential resonances existing in the unmeasured energy range and the complication of the effective nuclear potential. By comparing the cross sections of the three carbon isotope fusion reactions, ${}^{12}$C+${}^{12}$C, ${}^{12}$C+${}^{13}$C and ${}^{13}$C+${}^{13}$C, we have established an upper limit on the molecular resonance strengths in ${}^{12}$C+${}^{12}$C fusion reaction. The preliminary results are presented and the impact on nuclear astrophysics is discussed.Comment: 4 pages, 3 figures, FUSION11 conference proceedin

Non-Fermi Liquid Behavior in Dilute Quadrupolar System Prx_{x}La1−x_{1-x}Pb3_3 with xx≤\le0.05

We have studied the low-temperature properties of Pr$_{x}$La$_{1-x}$Pb$_{3}$ with non-Kramers $\Gamma_{3}$ quadrupolar moments of the crystal-electric-field ground state, for a wide concentration range of Pr ions. For $x$$\le$0.05, the specific heat $C/T$ increases monotonically below $T$=1.5 K, which can be scaled with a characteristic temperature $T^{*}$ defined at each concentration $x$. The electrical resistivity $\rho$$(T)$ in the corresponding temperature region shows a marked decrease deviating from a Fermi-liquid behavior $\rho$$(T)$$\propto$$T^{2}$. The Kondo effect arising from the correlation between the dilute $\Gamma_{3}$ moments and the conduction electrons may give rise to such anomalous behavior

Bubble wall perturbations coupled with gravitational waves

We study a coupled system of gravitational waves and a domain wall which is the boundary of a vacuum bubble in de Sitter spacetime. To treat the system, we use the metric junction formalism of Israel. We show that the dynamical degree of the bubble wall is lost and the bubble wall can oscillate only while the gravitational waves go across it. It means that the gravitational backreaction on the motion of the bubble wall can not be ignored.Comment: 23 pages with 3 eps figure

Detectability of Microwave Background Polarization

[NOTE: Previous versions of this paper (both on astro-ph and published in Phys. Rev. D) contain results that are in error. The power spectra C_l were normalized incorrectly by a factor of 2 pi. All observing times in detector-years in those versions are too large by a factor of 2 pi. The main place these numbers appear is on the vertical axes of Figures 4 and 5. Note that because all calculations were based on the same power spectra, all conclusions pertaining to comparisons of different techniques remain unchanged. This error has been corrected in the present version of the paper. An erratum is being sent to Phys. Rev. D. I apologize for the error.] Using a Fisher-matrix formalism, we calculate the required sensitivities and observing times for an experiment to measure the amplitudes of both E and B components as a function of sky coverage, taking full account of the fact that the two components cannot be perfectly separated in an incomplete sky map. We also present a simple approximation scheme that accounts for mixing of E and B components in computing predicted errors in the E-component power spectrum amplitude. In an experiment with small sky coverage, mixing of the two components increases the difficulty of detecting the subdominant B component by a factor of two or more in observing time; however, for larger survey sizes the effect of mixing is less pronounced. Surprisingly, mixing of E and B components can enhance the detectability of the E component by increasing the effective number of independent modes that probe this componentComment: Previous versions of this paper contained results that were in error. The present version on astro-ph has been corrected, and an erratum is being submitted. See abstract for detail

Coleman - de Luccia instanton of the second order in a brane world

The second order Coleman - de Luccia instanton and its action in the Randall - Sundrum type II model are investigated and the comparison with the results in Einstein's general relativity is done in the present paper.Comment: 4 pages, accepted in IJT

Optical study of the electronic phase transition of strongly correlated YbInCu_4

Infrared, visible and near-UV reflectivity measurements are used to obtain conductivity as a function of temperature and frequency in YbInCu_4, which exhibits an isostructural phase-transition into a mixed-valent phase below T_v=42 K. In addition to a gradual loss of spectral weight with decreasing temperature extending up to 1.5 eV, a sharp resonance appears at 0.25 eV in the mixed-valent phase. This feature can be described in terms of excitations into the Kondo (Abrikosov-Suhl) resonance, and, like the sudden reduction of resistivity, provides a direct reflection of the onset of coherence in this strongly correlated electron system.Comment: 4 pages, 3 figures (to appear in Phys. Rev. B