Quantum field theory represents a theoretical framework that explains the nature and behaviour of matter and energy at the atomic and subatomic level and that constructs quantum mechanical models of systems with an infinite number of degrees of freedom. It is also known as the natural language of both particle physics and condensed matter physics. Quantum theory and Albert Einstein's theory of relativity provide the foundation for modern physics. The principles of quantum physics are being applied in several areas such as quantum computing and quantum chemistry. This book is a welcomed addition to the current research which investigates the physical meaning and significance of information, and highlights the latest and most sophisticated concepts in quantum theory.