Dear all,
Vikesh Siddhu from Bob Griffiths group is visiting next Thursday, 29th. He would like to give an informal talk, so lets meet at 3pm in front of Renato's office (we'll move if this place is taken). Please let me know if this time is not good.
He is mainly visiting to meet people in the group, he stays only one day so please spare some time to tell him what you do if possible.
Here is the abstract he sent:
Title: Some qutrit channels with application to additivity of quantum capacity.
Abstract Understanding quantum communication capacity of noisy quantum channels is a central issue in qauntum information theory. One big challenge is posed by non-additivity of the quantum capacity.
A quantum channel has an associated isometry that maps the input to the output and environment. We introduce a simple class of channels called pcubed, for which the channel isometry maps a basis (generally non-orthogonal) of pure states at the input to pure states at the output.
Degradable channels are of interest because their one-shot quantum capacity is additive and equals the quantum capacity. Pcubed isometries can be used to produce a variety of degradable and non-degradable channels.
We have studied a two parameter family of pcubed qutrit channels which show interesting behaviour. Two such channels in parallel can exhibit either additive or non-additive behaviour of the one-shot quantum capacity.
Best,
Sandra