Quantum dissipation in vacuum neutrino oscillation

The pattern of neutrino oscillations changes when one considers these particles evolving as an open quantum system. In this article we derive seven possibilities that change the two-generation neutrino survival probability due to quantum dissipation and decoherence. We find entirely original probabilities assuming that these effects can be parametrized by the addition of only one phenomenological constant keeping complete positivity. We observe that a relaxation effect of the system shows an unusual mechanism of flavor conversion, the appearance of CP-violation effects for Majorana neutrinos, besides an appreciable change in the behavior of high energy neutrinos.