Topical Seminar: Non-adiabatic transitions in the density matrix formalism

por Sra. Shreya Pandit (U Southampton)

viernes 6 nov. 2026 12:00 → 13:30 Europe/Madrid

1001-Primera-1-1-1 - Paterna. Seminario (Universe)

Abstract: Non-adiabatic level crossings and quantum state transitions are fundamental phenomena occurring across a vast array of physical disciplines. In this talk, I will present a newly derived analytical expression for transition probability, for a two-state quantum system, in the non-adiabatic regime using Density Matrix Formalism (DMF) extending well beyond the traditional Landau-Zener-Stueckelberg-Majorana (LZSM) approximation. While standard LZSM treatment is restricted when considering complex time-dependent mixing or environmental interaction, our DMF framework accommodates both time-dependent dynamics and decoherence effects. Because of its general formulation, this framework applies to any two-state quantum system – offering a powerful analytical tool for particle physics and cosmology (such as active-sterile neutrino mixing, dark matter production and axion-photon mixing), as well as atomic physics, NMR, and quantum information. I will discuss the foundational derivation and illustrate its immediate application to solar neutrino oscillations, while opening the floor to broader prospective applications.