Sprecher
Beschreibung
Neutrinos propagating in environments with extremely strong magnetic fields can undergo spin and flavour transitions due to their non-zero magnetic moment, a phenomenon commonly referred to as neutrino spin-flavour precession. Such effects are expected to play an important role in dense and magnetized astrophysical settings, including supernovae and pulsars, where magnetic-field-induced transitions may significantly modify neutrino flavour and spin composition. Understanding these processes is therefore essential for accurate modelling of neutrino transport and flavour evolution in astrophysical media.
In the presence of strong magnetic fields, the effective Hamiltonian governing neutrino evolution includes contributions from vacuum flavour mixing, matter-induced interactions, and magnetic-field-driven spin–flavour transitions. In this work, we study the spin–flavour precession of neutrinos using a quantum simulation framework, focusing on a two-flavour neutrino system consisting of electron and muon neutrinos with both left- and right-handed helicity states. The resulting four-dimensional Hilbert space is evolved according to the Schrodinger equation.
We consider an initial left-handed electron neutrino state and encode it onto a two-qubit quantum system. The effective Hamiltonian is diagonalised via a suitable unitary transformation, enabling an efficient implementation of the time-evolution operator within a quantum-circuit model. After transforming the initial state into the Hamiltonian eigenbasis, phase gates corresponding to the eigenvalues are applied to simulate time evolution. The evolved state is subsequently transformed back into the flavour basis, allowing for the extraction of transition probabilities into the remaining spin–flavour states. The simulations are implemented using the Qiskit Aer simulator, and the resulting transition probabilities are systematically compared with analytical theoretical predictions. We find excellent agreement between the simulated and theoretical results, validating the accuracy of the quantum-circuit implementation. These results demonstrate that quantum simulation techniques can reliably reproduce key features of neutrino spin–flavour dynamics in strong magnetic-field environments.
This work provides a proof-of-principle demonstration of encoding neutrino spin–flavour evolution on a quantum platform, capturing essential neutrino-physics effects such as flavour mixing and magnetic-field induced transitions. The framework can be extended to include more realistic matter profiles, time-dependent magnetic fields, and additional neutrino flavours, offering a promising avenue for studying neutrino coherence and flavour evolution under supernova-like conditions relevant to next-generation neutrino observations.