Chirality of wavefunctions for three coalescing levels
The analytic structure in the vicinity of three coalescing eigenvalues (EP3) of a matrix problem is investigated. It is argued that the three eigenfunctions - also coalescing at the EP3 - invoke a true chiral behaviour in the vicinity of the EP3 and that they can be related to a three-dimensional helix. The orientation of the helix depends on the distribution of the widths of the three levels in the vicinity of the EP3. © 2008 IOP Publishing Ltd.