  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 allowed by quantum
mechanics while correlations are intrinsic (nonlocal) properties of composite
systems. There are four main problems that are addressed (i) the role played by
initial system-bath correlations on the subsystem dynamics of an open quantum
system, (ii) computation of correlations for two-qubit X-states, (iii) the
robustness of non-Gaussian entanglement under symmetric local noisy attenuator
and amplifier channels, and finally, (iv) the connection between
nonclassicality breaking and entanglement breaking for single-mode bosonic
Gaussian channels.
