Topic:  Note on Dirac monopole theory and Berry geometric phase

Speaker: Prof. Li-Chen Zhao

Coordinates: PCFT C1124, 16:00, Tuesday, October 15

Abstract:  We perform Dirac monopole theory in parameters space, after briefly introducing original Dirac string and non-integrable phase factor. Dirac string with endpoints are visualized  directly in parameters space for some simple models. The endpoints admit monopoles and correspond to degeneracy points of energy spectrum  for Hermitian models. The well-known Berry connection and curvature are derived by following the original Dirac monopole picture. These results suugest that Berry phase can be seen as the non-integrable phase factor induced by Dirac string with endpoints in the parameters space. We further show some cases for which it is hard to perforn Berry's framework, but Dirac's picture still works. The discussions would motivate more studies on geometric phases by performing Dirac's picture.