  Quantum effects arising from manifestly broken time-reversal symmetry are
investigated using time-dependent perturbation theory in a simple model. The
forward time and the backward time Hamiltonians are taken to be different and
hence the forward and backward amplitudes become unsymmetrical and are not
complex conjugates of each other. The effects vanish when the symmetry breaking
term is absent and ordinary quantum mechanical results such as Fermi Golden
rule are recovered.
