00-240 Asao Arai, Masao Hirokawa
Stability of Ground States in Sectors and Its Application to the Wigner-Weisskopf Model. (42K, LATeX 2e) May 23, 00
Abstract , Paper (src), View paper (auto. generated ps), Index of related papers

Abstract. We consider two kinds of stability (under a perturbation) of the ground state of a self-adjoint operator, being concerned with (i) the sector to which the ground state belongs and (ii) the uniqueness of the ground state. As an application to the Wigner-Weisskopf model which describes one mode fermion coupled to a quantum scalar field, we prove in the massive case the following: (a) For a value of the coupling constant, the Wigner-Weisskopf model has degenerate ground states ; (b) for a value of the coupling constant, the Wigner-Weisskopf model has a first excited state with energy level below the bottom of the essential spectrum.

Files: 00-240.tex