Charge-dependence of the πNN\pi NN coupling constant and charge-dependence of the NN interaction

The recent determination of the charged $\pi NN$ coupling constant, $g_{\pi^\pm}$, by the Uppsala Neutron Research Group implies that there may be considerable charge-splitting of the pion coupling constant. We investigate the consequences of this for the charge-independence breaking (CIB) of the $^1S_0$ scattering length, $\Delta a_{CIB}$. We find that $\Delta a_{CIB}$ depends sensitively on the difference between $g_{\pi^\pm}$ and the neutral $\pi NN$ coupling constant, $g_{\pi^0}$. Moreover, if $g^2_{\pi^\pm}$ is only about 3% larger than $g^2_{\pi^0}$, then the established theoretical explanation of $\Delta a_{CIB}$ (in terms of pion mass splitting) is completely wiped out.Comment: 9 pages, fbs styles, 1 figure; dedicated to Walter Gl\"ockle on the occasion of his 60th birthda

3-D inelastic analysis methods for hot section components. Volume 2: Advanced special functions models

This Annual Status Report presents the results of work performed during the third year of the 3-D Inelastic Analysis Methods for Hot Sections Components program (NASA Contract NAS3-23697). The objective of the program is to produce a series of computer codes that permit more accurate and efficient three-dimensional analyses of selected hot section components, i.e., combustor liners, turbine blades, and turbine vanes. The computer codes embody a progression of mathematical models and are streamlined to take advantage of geometrical features, loading conditions, and forms of material response that distinguish each group of selected components

Coexisting tuneable fractions of glassy and equilibrium long-range-order phases in manganites

Antiferromagnetic-insulating(AF-I) and the ferromagnetic-metallic(FM-M) phases coexist in various half-doped manganites over a range of temperature and magnetic field, and this is often believed to be an essential ingredient to their colossal magnetoresistence. We present magnetization and resistivity measurements on Pr(0.5)Ca(0.5)Mn(0.975)Al(0.025)O(3) and Pr(0.5)Sr(0.5)MnO(3) showing that the fraction of the two coexisting phases at low-temperature in any specified measuring field H, can be continuously controlled by following designed protocols traversing field-temperature space; for both materials the FM-M fraction rises under similar cooling paths. Constant-field temperature variations however show that the former sample undergoes a 1st order transition from AF-I to FM-M with decreasing T, while the latter undergoes the reverse transition. We suggest that the observed path-dependent phase-separated states result from the low-T equilibrium phase coexisting with supercooled glass-like high temperature phase, where the low-T equilibrium phases are actually homogeneous FM-M and AF-I phases respectively for the two materials

Hawking Radiation and Covariant Anomalies

Generalising the method of Wilczek and collaborators we provide a derivation of Hawking radiation from charged black holes using only covariant gauge and gravitational anomalies. The reliability and universality of the anomaly cancellation approach to Hawking radiation is also discussed.Comment: Minor changes, conforms to published versio

Quantum Tunneling, Blackbody Spectrum and Non-Logarithmic Entropy Correction for Lovelock Black Holes

We show, using the tunneling method, that Lovelock black holes Hawking radiate with a perfect blackbody spectrum. This is a new result. Within the semiclassical (WKB) approximation the temperature of the spectrum is given by the semiclassical Hawking temperature. Beyond the semiclassical approximation the thermal nature of the spectrum does not change but the temperature undergoes some higher order corrections. This is true for both black hole (event) and cosmological horizons. Using the first law of thermodynamics the black hole entropy is calculated. Specifically the $D$-dimensional static, chargeless black hole solutions which are spherically symmetric and asymptotically flat, AdS or dS are considered. The interesting property of these black holes is that their semiclassical entropy does not obey the Bekenstein-Hawking area law. It is found that the leading correction to the semiclassical entropy for these black holes is not logarithmic and next to leading correction is also not inverse of horizon area. This is in contrast to the black holes in Einstein gravity. The modified result is due to the presence of Gauss-Bonnet term in the Lovelock Lagrangian. For the limit where the coupling constant of the Gauss-Bonnet term vanishes one recovers the known correctional terms as expected in Einstein gravity. Finally we relate the coefficient of the leading (non-logarithmic) correction with the trace anomaly of the stress tensor.Comment: minor modifications, two new references added, LaTeX, JHEP style, 34 pages, no figures, to appear in JHE

Hawking Radiation, Covariant Boundary Conditions and Vacuum States

The basic characteristics of the covariant chiral current $$and the covariant chiral energy-momentum tensor$$ are obtained from a chiral effective action. These results are used to justify the covariant boundary condition used in recent approaches \cite{Isowilczek,Isoumtwilczek,shailesh,shailesh2,Banerjee} of computing the Hawking flux from chiral gauge and gravitational anomalies. We also discuss a connection of our results with the conventional calculation of nonchiral currents and stress tensors in different (Unruh, Hartle-Hawking and Boulware) states.Comment: 18 pages, no figures, minor changes, to appear in Phys. Rev.