ar X iv : c on d - m at / 9 60 11 22 v 1 2 5 Ja n 19 96 Learning and Generalization Theories of Large Committee – Machines

ar X iv : c on d - m at / 9 60 10 78 v 1 1 9 Ja n 19 96 Numerical Renormalization Group at Criticality

We apply a recently developed numerical renormalization group, the corner-transfer-matrix renormalization group (CTMRG), to 2D classical lattice models at their critical temperatures. It is shown that the combination of CTMRG and the finite-size scaling analysis gives two independent critical exponents.

ar X iv : c on d - m at / 9 60 10 85 v 1 1 9 Ja n 19 96 Coherent Charge Transport in Superconductor – Normal Metal Proximity Structures

We develop a detailed analysis of electron transport in normal diffusive conductors in the presence of proximity induced superconducting correlation. We calculated the linear conductance of the system and the profile of the electric field. A rich structure of temperature dependences was found and explained. Our results are consistent with recent experimental findings.

ar X iv : c on d - m at / 9 40 10 66 v 1 2 8 Ja n 19 94 Ground state energy and quasiparticle gaps

ar X iv : a lg - g eo m / 9 60 10 16 v 1 1 7 Ja n 19 96 SPACE OF CONFORMAL BLOCKS IN 4 D WZW THEORY Tohru Nakashima

An algebro-geometric definition of the space of conformal blocks in the 4D WZW theory is proposed. As an example, the dimensions of these spaces are calculated for ruled surfaces.

ar X iv : c on d - m at / 9 60 10 94 v 1 2 2 Ja n 19 96 Excitons in insulating cuprates

We study the electronic excitations near the charge-transfer gap in insulating CuO 2 planes, starting from a six-band model which includes p π and d xy orbitals and Cu-O nearest-neighbor repulsion U pd. While the low lying electronic excitations in the doped system are well described by a modified t−J model, the excitonic states of the insulator include hybrid d xy − p π states of A 2g symmetry...