An explicitly solvable model of the spontaneous <Emphasis Type="Italic">PT</Emphasis>-symmetry breaking

We contemplate the pair of the purely imaginary delta-function potentials on a finite interval with Dirichlet boundary conditions. The two parameter model exhibits nicely the expected quantitative features of the unavoided level crossing and of a “phase-transition” complexification of the energies. Combining analytic and numerical techniques we investigate strength- and position-dependence of spectrum. Presented at the 3rd International Workshop “Pseudo-Hermitian Hamiltonians in Quantum Physics”, Istanbul, Turkey, June 20–22, 2005.