Visualization of Branch Points inPT-Symmetric Waveguides

Visualization of branch points in PT-symmetric waveguides.

The visualization of an exceptional point in a PT-symmetric directional coupler (DC) is demonstrated. In such a system the exceptional point can be probed by varying only a single parameter. Using the Rayleigh-Schrödinger perturbation theory we prove that the spectrum of a PT-symmetric Hamiltonian is real as long as the radius of convergence has not been reached. We also show how one can use a ...

Normalized parameters for Y-branch optical waveguides.

Y-branch optical waveguides are analyzed in terms of normalized parameters by means of the usual modal analysis. With these parameters the number of variables of the problem is reduced, and universal plots for the mode conversion are obtained. Our results show that the normalized parameters are useful for the design of branching waveguides more tolerant of fabrication errors.

Coronary Spasm Preferentially Occurs at Branch Points

Background –Coronary spasm plays an important role in the pathogenesis of ischemic heart disease. However, similarities and differences between coronary spasm and atherosclerosis are not known. We examined the angiographic characteristics of coronary spasm in comparison with those of atherosclerosis. Methods and Results –Thirty two left anterior descending (LAD), 11 left circumflex (LCx) and 23...

Quantum toboggans with two branch points

In an innovated version of PT −symmetric Quantum Mechanics, wave functions ψ (x) describing quantum toboggans (QT) are defined along complex contours of coordinates x(s) which spiral around the branch points x . In the first nontrivial case with x ) = ±1, a classification is found in terms of certain “winding descriptors” ̺. For some ̺0, a mapping x (s) → y(s) is presented which rectifies the con...

Fixed Points of Symmetric Product Mappings