Quantificações de interferência em sistemas quânticos multipartidos

Abstract

By using the density matrix formalism, we analyze the phenomenon of genuine quantum interference for multipartite systems. The characterization and quantification of quantum correlations is of paramount importance to better understand quantum theory, as well as to correctly differentiate quantum correlations from classical ones. Among the quantum correlations, the most prominent one is entanglement, however, it is by no means the only one. Furthermore, the more complex the system, with regard to the number of constituents and the dimension of the Hilbert space that describes them, more types of quantum correlations can arise. Regarding the genuine quantum interference of two and three particles, studied in the course of this work, its manifestation occurs when analyzing the rates of joint detection of the constituent particles. In this case, there has been a consensus that, for this type of phenomenon to be observed, entanglement is necessary. However, as we will demonstrate at the end of this work, entanglement is not a requirement to verify these special types of interference, according to the approach presented here. In addition, we found that the interference quantifiers proposed here also serve to quantify entanglement, as long as they are applied to pure states.