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arXiv · 2606.24310

Non-adiabatic transitions in the density matrix formalism

Pasquale Di Bari·Shreya Pandit·Ye-Ling Zhou
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Abstract

We show that a density matrix formalism provides a useful description of non-adiabatic transitions in two-state quantum systems. Compared to a traditional Hamiltonian formalism, even in the absence of decoherence when there is full equivalence between the two, the density matrix formalism provides a convenient change of variables that yields a powerful general analytical solution. This solution nicely describes a transition regime between the well known Landau-Zener-Stuckelberg-Majorana (LZSM) approximation and the extremely non-adiabatic limit. Our results have very general applications, within a large variety of problems in quantum physics, neutrino physics, cosmology.

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Pasquale Di Bari, Shreya Pandit, Ye-Ling Zhou. 2026-06-23. Non-adiabatic transitions in the density matrix formalism. https://arxiv.org/abs/2606.24310

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