Entanglement Signatures of CPT Violation in Neutrino Oscillations

Abstract

We investigate the joint influence of CPT violation and quantum-gravity-induced Planck-scale corrections on the entanglement entropy of two-flavor neutrino oscillations. Building on the CPT-violating neutrino mass matrix arising from flavour-blind Planck-scale physics, we compute the von Neumann entanglement entropy separately for neutrinos and anti-neutrinos and demonstrate that CPT violation directly imprints an observable asymmetry in their entropy profiles. For a degenerate mass spectrum (m_{\nu}\simeq2\,\mathrm{eV}), non-zero Majorana phases a_{1} and a_{2} are required to reproduce the solar KamLAND discrepancy; these same phases control the amplitude of the entropy asymmetry. Our results establish that entanglement entropy provides a sensitive and novel probe of CPT-violating Planck-scale physics within neutrino phenomenology.