An Attempt to Derandomize the Random Unitary Matrices Used for Decoupling in Quantum Information Theory



Wednesday, 20 January 2016, 14:00 to 15:00



Abstract: The correlation of a quantum system to an initially correlated system  generally decreases when undergoes an evolution separated from E. Here we study the conditions under which the correlation disappears completely, resulting in a decoupling of from E. Decoupling is a general way to prove many coding theorems in quantum information theory. However existing decoupling constructions use random unitaries which are inefficient to implement. Hence the quest for derandomization.The talk shall describe the decoupling theorem and time permitting, sketch our attempt to derandomize it using a mathematical tool called unitary t-designs.