Experimental demonstration of the stability of Berry's phase for a spin-1/2 particle

TL;DR

This paper experimentally demonstrates that Berry's geometric phase for spin-1/2 particles remains stable and noise-resilient under cyclic magnetic field variations, highlighting its potential for robust quantum control.

Contribution

The study provides the first experimental evidence of the robustness of Berry's phase against adiabatic magnetic field fluctuations in a controlled setting.

Findings

Berry's phase remains stable over long evolution times.

Dephasing effects due to field fluctuations are suppressed.

Experimental validation using ultra-cold neutrons.

Abstract

The geometric phase has been proposed as a candidate for noise resilient coherent manipulation of fragile quantum systems. Since it is determined only by the path of the quantum state, the presence of noise fluctuations affects the geometric phase in a different way than the dynamical phase. We have experimentally tested the robustness of Berry's geometric phase for spin-1/2 particles in a cyclically varying magnetic field. Using trapped polarized ultra-cold neutrons it is demonstrated that the geometric phase contributions to dephasing due to adiabatic field fluctuations vanish for long evolution times.