Characterization of nonclassical states

The thesis consists of there sections. The first section introduces the notion of nonclassicality as disagreement of statistical properties of quantum light and the semiclassical theory of photodetection. Then different kinds of nonclassicality in terms of measurable quantities are presented: in terms of characteristic function and three kinds of moments. The second section is about one of the most intriguing phenomenon in quantum mechanics - entanglement. Here I present the complete conditions for negativity of partial transposition and show that several known results are just partial cases of this complete hierarchy of conditions. The final, third, section describes the measurement principles of the quantities needed for characterizing both nonclassicality and entanglement. The methods developed there have their own value as they allow one to measure the most general correlation function of a quantum field. (orig.)