On the character of chiral symmetry breaking and fermion vacuum structure in QE[D.sub.3]

Equation for the Bethe-Salpeter wave function of the Goldstone boson in QE[D.sub.3] is considered in the ladder approximation with the use of the Landau gauge for the photon propagator. With the help of standard simplifications, the existence of nonzero solutions for this equation is demonstrated, which testifies to the production of the above-described boson in the process of chiral symmetry breaking. At the same time, it is demonstrated that only one of the entire set of solutions describing the Goldstone boson corresponds to the stable ground state; this solution has the greatest fermion mass. In the remaining cases, the compound boson state with zero mass is excited, and all other states having smaller energies appear tachyon states and hence are unstable. The fermion condensate is calculated; it is demonstrated that in the examined case, it is finite. Based on the foregoing, conclusions are drawn about spontaneous rather than dynamic character of chiral symmetry breaking in QE[D.sub.3], complex structure of fermion vacuum for the examined model, and at the same time, simple structure of the massive phase vacuum. Keywords: chiral symmetry, Bethe-Salpeter wave function, ladder approximation, Goldstone boson, tachyon, dynamic fermion mass, fermion condensate, fermion vacuum.