  Quantum information theory is the study of the achievable limits of
information processing within quantum mechanics. Many different types of
information can be accommodated within quantum mechanics, including classical
information, coherent quantum information, and entanglement. Exploring the rich
variety of capabilities allowed by these types of information is the subject of
quantum information theory, and of this Dissertation. In particular, I
demonstrate several novel limits to the information processing ability of
quantum mechanics. Results of especial interest include: the demonstration of
limitations to the class of measurements which may be performed in quantum
mechanics; a capacity theorem giving achievable limits to the transmission of
classical information through a two-way noiseless quantum channel; resource
bounds on distributed quantum computation; a new proof of the quantum noiseless
channel coding theorem; an information-theoretic characterization of the
conditions under which quantum error-correction may be achieved; an analysis of
the thermodynamic limits to quantum error-correction, and new bounds on channel
capacity for noisy quantum channels.
