Abstract To understand the mechanism of the fermion pair and fermion-antifermion pair condensation,existence of the solutions of Bethe-Salpeter equation in QED3 is examined.In the ladder appoximation our solution for the axialscalar is consistent with Ward-Takahashi-identity for the axial vector currents.In addition to massless psedoscalar fermion-antifermion (fa) system there exists solutions ...

We propose a new approach to the fermion sign problem in systems where there is a coupling U such that when it is infinite the fermions are paired into bosons, and there is no fermion permutation sign to worry about. We argue that as U becomes finite, fermions are liberated but are naturally confined to regions which we refer to as fermion bags. The fermion sign problem is then confined to thes...

In this paper, at first we have formulated the lowest order constrained variational method for the relativistic case of an interacting fermion system at finite temperature. Then we have used this formalism to calculate some thermodynamic properties of liquid in the relativistic regime. The results show that the difference between total energies of relativistic and non-relativistic cases of liqu...

In various dimensional euclidean lattice gauge theories, we examine a compatibility of the Majorana decomposition and the charge conjugation property of lattice Dirac operators. In 8n and 1+8n dimensions, we find a difficulty to decompose a classical lattice action of the Dirac fermion into a system of the Majorana fermion and thus to obtain a factrized form of the Dirac determinant. Similarly,...

We construct supersymmetric gauge theories with new mechanisms of dynamical supersymmetry breaking. The models have flat directions at the classical level, and different mechanisms lift these flat directions in different regions of the classical moduli space. In one branch of the moduli space, supersymmetry is broken by confinement in a novel manner. The models contain only dimensionless coupli...

We introduce a criterion named macroscopic spontaneously symmetry breaking, for short MSSB, for general quasi-local systems with any statistics. It is formulated based on the idea that each pair of distinct phases (appeared in spontaneous symmetry breaking) should be disjoint not only for the total system but also for every outside system of a local region specified by the given quasi-local str...