Breaking of PT-symmetry in bounded and unbounded scattering systems
Makris, Konstantinos G.
Stone, A. Douglas
Date of Issue2013
School of Physical and Mathematical Sciences
PT-symmetric scattering systems with balanced gain and loss can undergo a symmetry-breaking transition in which the eigenvalues of the nonunitary scattering matrix change their phase shifts from real to complex values. We relate the PT-symmetry-breaking points of such an unbounded scattering system to those of the underlying bounded systems. In particular, we show how the PT thresholds in the scattering matrix of the unbounded system translate into analogous transitions in the Robin boundary conditions of the corresponding bounded systems. Based on this relation, we argue and then confirm that the PT transitions in the scattering matrix are, under very general conditions, entirely insensitive to a variable coupling strength between the bounded region and the unbounded asymptotic region, a result that can be tested experimentally and visualized using the concept of Smith charts.
Physical review X
© 2013 American Physical Society. This paper was published in Physical Review X and is made available as an electronic reprint (preprint) with permission of American Physical Society. The paper can be found at the following official DOI: [http://dx.doi.org/10.1103/PhysRevX.3.041030]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.