Title: Complex extension of quantum theories

Speaker: Prof. Bhabani Prasad Mandal, BHU

Abstract: Non-Hermitian extension of usual quantum theories has become a very interesting topic in frontier research over the last two decades It is possible to have fully consistent quantum theories for non-Hermitian but PT symmetric systems in a modified Hilbert space endowed with appropriate inner product. Such systems have been studied extensively and found many applications in quantum mechanics, quantum field theories and more recently in optics. Such systems generally exhibit PT phase transition. The consequence of this PT phase transition has been experimentally observed in analogous classical systems. This experimental realizations give a huge boost to this new branch of physics and hence this formulation has naturally been extended to many other branches of physics, namely information theory, condensed matter theories, non-linear theories, statistical mechanics, many particle integrable systems, rationally extended solvable and quasi exactly solvable systems etc. The purpose of this talk is to give a zero level introduction to this subject and mention few interesting features of this new branch. I will briefly comment on some of our contributions in this field towards the end.