RESONANT STATES IN THE THERMO FIELD-DYNAMICS

The formalism of the thermo field dynamics (TFD) is extended in order to accommodate resonant states belonging to the spectrum of a single-p article Hamiltonian. It is shown that the rules of the TFD can be appl ied to a fermionic basis where resonant states are described as comple x eigenvalues. The consequences for the definition of TFD thermodynami cal observables, due to the inclusion of resonant states, are studied. (C) 1998 Elsevier Science B.V.