ar X iv : c on d - m at / 9 90 72 32 v 1 1 6 Ju l 1 99 9 Radiation from an electron bunch flying over a surface wave

ar X iv : c on d - m at / 9 30 70 57 v 1 2 8 Ju l 1 99 3 A comparison of FQHE quasi - electron trial wave functions on the disk

The various proposals for FQHE quasi-electron trial wave functions are reconsidered. In a short-range model for the electronic interaction, the energy expectation values of four different trial wave functions are calculated at filling factor 1 3 for up to ten electrons in the disk geometry. Jain's trial wave function displays the lowest energy expectation value.

ar X iv : c on d - m at / 9 60 72 23 v 1 3 1 Ju l 1 99 6 Hofstadter butterflies for flat bands

Hofstadter’s diagram, or the energy spectrum against the magnetic field in tight-binding systems, is obtained for the models having flat (dispersionless) one-electron band(s) that have originally been proposed for itinerant spin ferromagnetism. Magnetic fields preserve those flat bands that arise from a topological reason, while dispersions emerge in a singular manner for the flat bands arising...

ar X iv : c on d - m at / 9 60 31 90 v 1 2 9 M ar 1 99 6 The Four - Dimensional XY Spin Glass

ar X iv : c on d - m at / 9 60 72 14 v 1 3 0 Ju l 1 99 6 Spontaneous vortex phase discovered ?

It is argued that a spontaneous vortex phase may exist in the recently discovered compound ErN i 2 B 2 C at temperature below 2.3K. The consequences of this proposal are discussed. In particular the magnetic response of the system are studied both above and below 2.3K and further experiments proposed.

ar X iv : n uc l - th / 9 90 60 29 v 3 1 5 Ju l 1 99 9 1 Quark Matter ’ 99 — Theoretical Summary : What Next ?