Two PT symmetry topics

New results are reported on two PT-symmetry topics. In the first part of the talk, an entanglement related quantum state discrimination scheme is described which is based on the fine-tuned Naimark-dilation of a PT-symmetric subsystem in 2D Hilbert space. (Work together with Carl M. Bender, Dorje C. Brody and Boris F. Samsonov). In the second part of the talk, the stability properties of nonlinear PT-symmetric 2D
plaquettes are discussed. Specific emphasis is laid on the role of the nonlinear terms in shifting the PT-threshold of associated linear systems. This part of the talk is based on common work with Panayotis Kevrekidis, Kai Li and Boris Malomed (arXiv:1204.5530[quant-ph]) as well as on newer results going beyond the findings in this e-print.