Ground States of S-duality Twisted N=4 Super Yang-Mills Theory

We study the low-energy limit of a compactification of N=4 U(n) super Yang-Mills theory on $S^1$ with boundary conditions modified by an S-duality and R-symmetry twist. This theory has N=6 supersymmetry in 2+1D. We analyze the $T^2$ compactification of this 2+1D theory by identifying a dual weakly coupled type-IIA background. The Hilbert space of normalizable ground states is finite-dimensional and appears to exhibit a rich structure of sectors. We identify most of them with Hilbert spaces of Chern-Simons theory (with appropriate gauge groups and levels). We also discuss a realization of a related twisted compactification in terms of the (2,0)-theory, where the recent solution by Gaiotto and Witten of the boundary conditions describing D3-branes ending on a (p,q) 5-brane plays a crucial role.Comment: 104 pages, 5 figures. Revisions to subsection (6.6) and other minor corrections included in version

N_pN_n dependence of empirical formula for the lowest excitation energy of the 2^+ states in even-even nuclei

We examine the effects of the additional term of the type $\sim e^{- \lambda' N_pN_n}$ on the recently proposed empirical formula for the lowest excitation energy of the $2^+$ states in even-even nuclei. This study is motivated by the fact that this term carries the favorable dependence of the valence nucleon numbers dictated by the $N_pN_n$ scheme. We show explicitly that there is not any improvement in reproducing $E_x(2_1^+)$ by including the extra $N_pN_n$ term. However, our study also reveals that the excitation energies $E_x(2_1^+)$, when calculated by the $N_pN_n$ term alone (with the mass number $A$ dependent term), are quite comparable to those calculated by the original empirical formula.Comment: 14 pages, 5 figure

Preliminary Studies about Synthesis and Electrical Properties of Ruthenium Doped Lanthanum Strontium Titanate as a Potential Anode of Solid Oxide Fuel Cells

The lanthanum strontium titanate (LST) is one of the most representative alternative anode materials. Although it shows low catalytic properties, the disadvantage could be improved by doping of ruthenium which is widely used as catalyst under steam reforming reaction or oxidation reaction. The ruthenium doped lanthanum strontium titanates (LSTRs) powders were synthesized by complex EDTA-citrate method showing well crystallinity. Additionally, the prepared samples were evaluated through various experimental tests. For example, the stability in the reducing atmosphere and chemical compatibility with YSZ electrolyte such as reactivity test in high temperature were confirmed by XRD (X-ray diffraction). And electrical conductivity in wet H-2 atmosphere at 900 degrees C is about 350.6 S/cm, 342.4 S/cm and 179.1 S/cm with sintered bar of LST, LSTR0.02 and LSTR0.05, respectively.open1111Nsciescopu