Fermi Liquid without Quasiparticles and Electron Spectral Functions of Two-Dimensional High-TcT_c Superconductors

Properties of strongly correlated two-dimensional (2D) electron systems in solids are studied on the assumption that these systems undergo a phase transition, called fermion condensation, whose characteristic feature is flattening of the electron spectrum \epsilon({\pf p}). Unlike the previous models in the present study, the decay of single-particle states is properly taken into account. Remarkably, the value of the topological charge ($N=1/2$) remains unchanged, supporting the view that systems with a fermion condensate form a separate class of Fermi liquids. Results of calculations are found to be in qualitative agreement with ARPES data.Comment: 13 pages, 3 figure

Fermion theories on a 2d torus with Wilson action improved by Pauli -- Villars regularization

Vectorial and anomaly free chiral U(1) fermion models on a 2d finite lattice are considered. It is demonstrated both numerically and analytically that introduction of Pauli -- Villars type regularization supresses the symmetry breaking effects caused by the Wilson term.Comment: 17 pages, Latex, 6 eps-figure