We consider the one-dimensional Dirac equation for the harmonic oscillator
and the associated second order separated operators giving the resonances of
the problem by complex dilation. The same operators have unique extensions as
closed PT-symmetric operators defining infinite positive energy levels
converging to the Schroedinger ones as c tends to infinity. Such energy levels
and their eigenfunctions give directly a definite choice of metastable states
of the problem. Precise numerical computations shows that these levels coincide
with the positions of the resonances up to the order of the width. Similar
results are found for the Klein-Gordon oscillators, and in this case there is
an infinite number of dynamics and the eigenvalues and eigenvectors of the
PT-symmetric operators give metastable states for each dynamics.Comment: 13 pages, 2 figure