Quantum magic and computational complexity in the neutrino sector
Ivan A. Chernyshev, Caroline Robin, Martin J. Savage A · Physical Review Research · 2025
We consider the quantum magic in systems of dense neutrinos undergoing coherent flavor transformations, relevant for supernova and neutron-star binary mergers. Mapping the three-flavor-neutrino system to qutrits, the evolution of quantum magic is explored in the single scattering angle limit for a selection of initial tensor-product pure states for N ν ≤ 8 neutrinos. For | ν e 〉 ⊗ N ν initial states, the magic, as measured by the α = 2 stabilizer Renyi entropy M 2 , is found to decrease with radial distance from the neutrino sphere, reaching a value that lies below the maximum for tensor-product qutrit states. Further, the asymptotic magic per neutrino, M 2 / N ν , decreases with increasing N ν . In contrast, the magic evolving from states containing all three flavors reaches values only possible with entanglement, with the asymptotic M 2 / N ν increasing with N ν . These results highlight the connection between the complexity in simulating quantum physical systems and the parameters of the Standard Model.