Iterative solutions for low lying excited states of a class of SchrSdinger equation

The convergent iterative procedure for solving the groundstate Schr?dinger equation is extended to derive the excitation energy and the wavefunction of the low-lying excited states. The method is applied to the one-dimensional quartic potential problem. The results show that the iterative solution converges rapidly when the coupling g is not too small.     

Superconductivity in PdAlx hydrides

Hydrides of PdA$\text{l}$_x alloys prepared by electron beam co-evaporation and subsequent implantation of hydrogen ions are found to exhibit anomalous changes in the superconducting transition temperature with increasing A$\text{l}$ content. At large hydrogen concentrations, H/Pd ～ 1, the addition of aluminum increases T_c only slightly (from 8.1 to 8.6°K for 7 at. % A$\text{l}$), and then yields an abrupt decrease in T_c at 10% A$\text{l}$. This behavior is in sharp contrast to PdAg_xH_y alloys which exhibit an enhanced T_c ～ 16°K at relatively low silver content.     

Eigenvalues of collective emission in multi-slice slab configurations

We compute the eigenmodes of collective emission from multi-slice slab configurations, using the transfer matrix formalism. We elucidate within this formalism the phenomena of “Invisible Gaps” in multiple-slice configuration and of “Precocious Superradiance” in periodic structures previously observed in numerical solutions of Maxwell-Bloch equations.     

Effects of including the counterrotating term and virtual photons on the eigenfunctions and eigenvalues of a scalar photon collective emission theory

We find eigenmodes of an integral equation describing N 2-level atoms interacting with a scalar field, one atom being initially excited. Neglect of virtual field quanta would replace the correct kernel by its real part. This has serious consequences both for small and large samples.     

Integral equation formulation for buoyancy-driven convection problems

An integral equation formulation for buoyancy-driven convection problems is developed and illustrated. Buoyancy-driven convection in a bounded cylindrical geometry with a free surface is studied for a range of aspect ratios and Nusselt numbers. The critical Rayleigh number, the nature of the cellular motion, and the heat transfer enhancement are computed using linear theory. Green's functions are used to convert the linear problem into linear Fredholm integral equations. Theorems are proved which establish the properties of the eigenvalues and eigenfunctions of the linear integral operator which appears in these equations.