arXiv:2111.05401 · Physical review. D/Physical review. D.
Scalable qubit representations of neutrino mixing matrices
M. J. Molewski, B. J. P. Jones
Abstract
Oscillating neutrino beams exhibit quantum coherence over distances of thousands of kilometers. Their unambiguously quantum nature suggests an appealing test system for direct quantum simulation. Such techniques may enable presently analytically intractable calculations involving multineutrino entanglements, such as collective neutrino oscillations in supernovas, but only once oscillation phenomenology is properly reexpressed in the language of quantum circuits. Here we resolve outstanding conceptual issues regarding encoding of arbitrarily mixed neutrino flavor states in the Hilbert space of an n-qubit quantum computer. We introduce algorithms to encode mixing and oscillation of any number of flavor-mixed neutrinos, both with and without $CP$-violation, with an efficient number of prescriptive input parameters in terms of subrotations of the Pontecorvo-Maki-Nakagawa-Sakata matrix in standard form. Examples encoded for an IBM-Q quantum computer are shown to converge to analytic predictions both with and without $CP$-violation.