Manifestation of topological phase in neutron spin rotation without adiabatic regime

TL;DR

This paper demonstrates that topological phases in neutron spin rotation can be observed without adiabatic conditions, using analytical solutions and numerical simulations that align with experimental data.

Contribution

It reveals that nonadiabatic conditions can still manifest topological phases in neutron spin rotation, extending previous understanding beyond adiabatic regimes.

Findings

Nonadiabatic topological phase matches experimental data

Analytical solutions for neutron spin in rotating systems

Topological phase observed in complex, dynamic scenarios

Abstract

The Bitter-Dubbers (BD) experiment is an important experiment that originally aimed to measure topological phase using polarized-neutron spin rotation in a helical magnetic field under adiabatic conditions. Contrary to expectations, upon reevaluation of the BD experiment, it has been found that adiabatic conditions are not necessary for measuring topological phase. In scenarios where the magnetic field is neither homogeneous nor strong enough, and the neutron has a fast velocity, the topological phase can still be manifested. To demonstrate this, we analytically solve the time-dependent Schrodinger equation for the neutron spin rotation in general rotating systems. These exact solutions are then utilized to investigate the nonadiabatic topological phase under the conditions mentioned above. The numerical simulations of the nonadiabatic topological phase have shown a strong concurrence with the BD experimental data. This novel result extends our understanding of the topological phase observed in neutron spin rotation, even in more complex and dynamic scenarios beyond the originally required adiabatic conditions.