About the neutrino oscillation-like effects in general physical systems

Abstract

We evidence the main theoretical properties determining that neutrino oscillations appear as an interference between fully distinguishable particles. The source of the effect is identified as the many-particle structure of space of states of a quantum field theory. It is underlined that the space of states for neutrinos in the SM is the linear completion of the direct product of the three neutrino Fock spaces. Then, this nature of the state space directly makes clear that the neutrino oscillations become interference effects among non-identical particles; which are exclusively generated by essentially many particle states being always outside the direct product of the three neutrino Fock spaces. This cleanly many-particle effect is then identified as the central reason breaking the usual single particle quantum mechanical rule, not allowing the interference between distinguishable particles. The work also examines the connections with the Vitiello–Blasone analysis about the role of QFT in neutrino oscillations. It is argued that their evaluation corresponds to a more natural representation of the perturbative expansion for the applications in neutrino oscillations. However, the results coincide with the usual and ours simpler evaluations, in the large momentum limit. One conclusion of the work is that similar interference effects should be present in many physical systems. By example, among them are all the ones described by a QFT including at least two kinds of distinguishable particles having similar mass values. For illustrating this point, a band model of a solid is presented which shows oscillations analogous to the neutrino ones, but happening between two electron waves propagating in different bands.