New physics effects on quantum coherence in neutrino oscillations

Abstract

Several measures of quantum correlations such as Leggett–Garg and Bell-type inequalities have been extensively studied in the context of neutrino oscillations. However, these analyses are performed under the assumption of standard model (SM) interactions of neutrinos. In this work, we study new physics effects on $l_1$-norm based measure of quantum coherence which quantifies the quantumness embedded in the system and is also intrinsically related to various measures of quantum correlations. Moreover, it is considered to be a resource theoretical tool which can be utilized in quantum algorithms and quantum channel discrimination. The new physics effects are incorporated in a model independent way by using the effective Lagrangian for the neutral current non-standard neutrino interactions (NSI). Bounds on the NSI parameters are extracted from a recent global analysis of oscillation experiments including COHERENT (coherent neutrino-nucleus scattering experiment) data. In the context of upcoming DUNE experimental setup, we find that the most favourable combination of LMA-Light sector of $\theta _{12}$ (i.e., $\theta _{12}< 45^{\circ }$) with normal mass ordering decreases the coherence in the system in comparison to the SM prediction for all values of neutrino energy E and CP violating phase $\delta$ (except in the narrow region around $E \sim$ 2 GeV). On the other hand, a large enhancement in the value of coherence parameter in the entire $(E-\delta )$ plane is possible for the dark octant of $\theta _{12}$ ($\theta _{12}> 45^{\circ }$) with inverted ordering. For almost all values of CP violating phase, the enhancement is more protuberant in the region around $E \sim$ 4 GeV where maximum neutrino flux is expected in the DUNE experiment. Therefore for the normal mass ordering, the SM interaction provides favourable conditions for quantum information tasks while the NSI favours inverted ordering scenario for such tasks.