The exceptional point, known as the non-Hermitian degeneracy, has special topological structure, leading to various counterintuitive phenomena and novel applications, which are refreshing our cognition of quantum physics. One particularly intriguing behavior is mode switch phenomenon induced by dynamically encircling an point in parameter space. While these switches have been explored classical...

One of the most enchanting tourist trips in Europe is along the Rhine Valley with the winding river surrounded by hills topped by many medieval castles. On the Neckar River, a tributary to the Rhine, lies the beautiful historic city of Heidelberg, again with a magnificent castle looking down on the old city from a nearby hill. Heidelberg, the home of Germany’s oldest university established in 1...

Two cases of recurrent perianal suppuration are described in which the underlying pathology is believed to be pilonidal sinus disease affecting the perianal skin directly. This has given rise to intersphincteric fibrosis and, in one case, a subcutaneous track almost completely encircling the anus. The pathogenesis of the condition and its possible relationship to previous surgery are discussed.

A method of measuring the extent to which space curves encircle one another is introduced. The method provides a family of sets which characterize encircling curves, allowing curve pairs that engage (and also single curves that self-engage) to be distinguished. The method is applied to the backbone chains of protein molecules.

It is shown that the molecular Aharonov-Bohm effect is neither nonlocal nor topological in the sense of the standard magnetic Aharonov-Bohm effect. It is further argued that there is a close relationship between the molecular Aharonov-Bohm effect and the Aharonov-Casher effect for an electrically neutral spin -1 / 2 particle encircling a line of charge.

We developed a novel click-free interface for laser-pointer-based systems with wall-sized screens. The technique includes two moving operations: “crossing,” which uses four edges as a crossing target to execute a command, and “encircling,” which selects objects by drawing a circle around them. This paper describes the proposed interface, its implementation, and an experiment conducted to test t...