Tony Dorlas (DIAS-Dublin, Ireland)
Optimal coding of classical messages
for a quantum channel with memory.
We prove an analogue of the Holevo-Schumacher-Westmoreland theorem
for a quantum channel which is a probabilistic mixture of memoryless
channels.
This is an interesting class of channels because it is the simplest
example
of
a channel with long-term memory and ergodicity fails. The result is a
supremum over
the minimum of Holevo quantities corresponding to the different
branches of
the channel.
This work is a collaboration with Nilanjana Datta (Cambridge).