Abstract
We describe a novel class of quantum mechanical particle oscillations in both relativistic and non-relativistic systems based on PT symmetry and T²=-1 (relevant for fermions), where P is parity and T is time reversal. The Hamiltonians are chosen at the outset to be self-adjoint with respect to a PT inner product. The quantum mechanical time evolution is based on a modified CPT inner product constructed in terms of a suitable C operator. The resulting quantum mechanical evolution is shown to be unitary and probability is conserved by the oscillations.