Berry's phase in the presence of a non-adiabatic environment with an application to magnetic resonance.
We consider a two-level system coupled to an environment that evolves non-adiabatically. We present a non-perturbative method for determining the persistence amplitude whose phase contains all the corrections to Berry's phase produced by the non-adiabatic motion of the environment. Specifically, it includes the effect of transitions between the two energy levels to all orders in the non-adiabatic coupling. The problem of determining all non-adiabatic corrections is reduced to solving an ordinary differential equation to which numerical methods should provide solutions in a variety of situations. We apply our method to a particular example that can be realized as a magnetic resonance experiment, thus raising the possibility of testing our results in the laboratory.
Gaitan
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Department of Physics, Boston College, Chestnut Hill, Massachusetts 02167-3811, USA.
D009682:Magnetic Resonance Spectroscopy / Q000379:methods*