Ciara Morgan
Ultimate limits for quantum communication
Establishing the optimal communication rate at which information can be
reliably transmitted over noisy quantum channels is a question of central
importance in quantum information theory. The achievability, or direct
part, of a channel coding theorem, establishes a rate of communication
below which the decoding error tends to zero in the limit of large block
length. This raises the natural question of whether a larger rate can be
achieved with a non-zero decoding error. In other words, the question of
whether an error-rate trade-off is possible emerges. The strong converse
theorem addresses this question and when established for a particular
channel, confirms that there can be no such error-rate trade-off for that
channel. The question of whether a strong converse theorem holds for all
quantum channels remains open.
In this talk the above concepts will be introduced and ongoing efforts
towards attacking this open problem will be reported.