Fig. 4: Wilson loop.
From: Wilson loop and Wilczek-Zee phase from a non-Abelian gauge field
a \(| {W}_{{{{{\mathcal{C}}}}}_{\pm }}|\) for forward (\({W}_{{{{{\mathcal{C}}}}}_{+}}\), blue diamonds) and reverse (\({W}_{{{{{\mathcal{C}}}}}_{-}}\), red circles) ramps are plotted along with theory (solid curve). At Ξ = 0 (θ2 = π/2), the circular paths reduce to a point, which we trivially measure with T = 0 ms (green diamond). b The phase difference of the eigenvalues of W.-Z phase factor \(| \delta {\lambda }_{{{{{\mathcal{C}}}}}_{\pm }}|\) obtained from the WL measurement in a, with the same symbols. Inset: In the complex plane, the eigenvalues appear on the unit circle (pink and green points), and sum to \({W}_{{{{\mathcal{C}}}}}\) (red arrow).
