The next Q+ hangout is on the coming Tuesday:

Speaker: Prof. Andreas Winter, Bristol University
Date: 27th of September, 14:00 BST
Title: Zero-error communication via quantum channels, non-commutative graphs and a quantum Lovasz theta-function
Abstract: I will review some of the recent progress on the zero-error capacity problem for quantum channels, centered mainly around my work with Runyao Duan and Simone Severini [1002.2514], which suggests an extension of graphs and graph notions into the non-commutative domain.

For info how to join please see below.