Nodal free geometric phases: Concept and application to geometric quantum computation
arXiv:0708.0749 · doi:10.1016/j.physleta.2007.08.022
Abstract
Nodal free geometric phases are the eigenvalues of the final member of a parallel transporting family of unitary operators. These phases are gauge invariant, always well-defined, and can be measured interferometrically. Nodal free geometric phases can be used to construct various types of quantum phase gates.
Small typo corrected, journal reference added