Different aspects of non-Hermitian quantum theories

Recently the study of certain classes of non-Hermitian quantum systems have been attracted lots of interests as one can have fully consistent quantum theories by restoring the hermiticity and by upholding the unitary time evolution for such systems in a modified Hilbert space. In this talk we discuss various formal as well as implementable aspects of non-Hermitian quantum theories in different branches of physics particularly in quantum information theories, many-particle physics and in quantum optics.