This book discusses the elementary ideas and tools needed for open
quantum systems in a comprehensive manner. The emphasis is given to both
the traditional master equation as well as the functional (path)
integral approaches. It discusses the basic paradigm of open systems,
the harmonic oscillator and the two-level system in detail. The
traditional topics of dissipation and tunneling, as well as the modern
field of quantum information, find a prominent place in the book.
Assuming a basic background of quantum and statistical mechanics, this
book will help readers familiarize with the basic tools of open quantum
systems.
Open quantum systems is the study of quantum dynamics of the system of
interest, taking into account the effects of the ambient environment. It
is ubiquitous in the sense that any system could be envisaged to be
surrounded by its environment which could naturally exert its influence
on it. Open quantum systems allows for a systematic understanding of
irreversible processes such as decoherence and dissipation, of the
essence in order to have a correct understanding of realistic quantum
dynamics and also for possible implementations. This would be essential
for a possible development of quantum technologies.