Abstract
Ciara Morgan (CQT-NUS)
Quantum information, channels and capacity
Alice would like to send Bob a private message. Alice encodes her message into quantum states and sends it to Bob via a quantum channel. However, the quantum channel contains some noise which may interfere with, and alter her message, and so she must be smart about how she encodes her message so that Bob will be able to recover it, with low probability of error. During the seminar, we will introduce the classical capacity of quantum channels, that is, the maximum rate at which output-states from a classical source, encoded into codewords comprising of quantum states taken from an ensemble, can be transmitted reliably over a quantum channel. We are interested in the type of states and ensembles which achieve the information-carrying capacity of quantum channels, subject to certain types of noise. We will introduce some quantum channels and discuss the enhancement of quantum channel capacity using entangled input-states.