Gamow Functionals on Operator Algebras
  We obtain the precise form of two Gamow functionals, representing the exponentially decaying part of a quantum resonance and its mirror image that grows exponentially, as a linear, positive and continuous functional on an algebra containing observables. These functionals do not admit normalization and, with an appropiate choice of the algebra, are time reversal of each other. 
M. Castagnino, M. Gadella, R. Id Betan, R. Laura