Imagine that a physical system is changed – e.g., by variation of external fields – such that at the end everything is adjusted exactly as in the beginning but one obtains different physical results. This can happen if losses – e.g., light propagating in an absorbing material – become important. Sometimes even lasers only work if they lose light intensity. Such apparently surprising effects in quantum physics and optics are presented in the talk and their origins are investigated.
Holger Cartarius is an academic staff member in the Physics Education division of the University of Stuttgart. He researches on courses on modern physics and the mathematics education of physics teaching candidates. Prior to this he was active in theoretical physics. He studied physics and did his doctorate at the Institute of Theoretical Physics 1 at the University of Stuttgart. After a postdoc stay at the Weizmann Institute of Science in Rehovot, Israel, he returned to Stuttgart where he did his Habilitation in theoretical physics with a work on effective theories on open quantum systems.