This book highlights the applications of continuous-variable entangled state representations in the research areas of quantum optics via the integration method within an ordered product of operators (IWOP). As a way to develop the Dirac’s symbolic method, the IWOP method has made the integration of non-commutative operators possible by arranging non-commutable operators within an ordered product symbol. It not only deals with many existent quantum optics problems but also explores new rese...