Some aspects of the interplay between bipartite correlations and quantum channels[HBNI Th65]

Abstract

This thesis explores ways in which quantum channels and correlations (of both classical and quantum types) manifest themselves, and also studies the interplay between these two aspects in various physical settings. Quantum channels represent all possible evolutions of states, including measurements, allowed by quantum mechanics, while correlations are intrinsic (nonlocal) properties of composite systems. It is the interplay between correlations of bipartite states and their evolution through quantum channels that is the unifying theme of this thesis. There are four broad topics that are covered in this thesis : • Initial bipartite correlations and induced subsystem dynamics : Does initial correlation of the system-bath states provide a generalization of the folklore product realization of CP maps • A geometric approach to computation of quantum discord and classical correlations for all two-qubit X-states.

• Robustness of nonGaussian vs Gaussian entanglement against noisy amplifier and attenuator environments. • Is nonclassicality breaking the same thing as entanglement breaking?