Non-Adiabatic Fluctuation in Measured Geometric Phase

TL;DR

This paper investigates how non-adiabatic effects cause fluctuations in the geometric phase of a two-level quantum system, explaining experimental observations in superconducting circuits beyond conventional errors.

Contribution

It provides an analysis based on Rabi's exact solution to explain observed phase fluctuations as non-adiabatic effects in geometric phase measurements.

Findings

Non-adiabatic effects induce measurable geometric phase fluctuations.

Rabi's exact solution explains experimental phase fluctuations.

Clarifies the role of non-adiabaticity in quantum geometric phases.

Abstract

We study how the non-adiabatic effect causes the observable fluctuation in the "geometric phase" for a two-level system, which is defined as the experimentally measurable quantity in the adiabatic limit. From the Rabi's exact solution to this model, we give a reasonable explanation to the experimental discovery of phase fluctuation in the superconducting circuit system [P. J. Leek, \textit{et al}., Science \textbf{318}, 1889 (2007)], which seemed to be regarded as the conventional experimental error.