Patrick Hayden: Quantum information as asymptotic geometry

Monday, November 15, 2010 12:30 pm - 1:30 pm EST (GMT -05:00)

Patrick Hayden, McGill

Quantum states are represented as vectors in an inner product space. Because the dimension of that state space grows exponentially with the number of its constituents, quantum information theory is in large part the asymptotic theory of finite dimensional inner product spaces, a field with its own long history. I’ll highlight some examples of how abstract mathematical results from that area, such Dvoretzky’s theorem, manifest themselves in quantum information theory as improvements on teleportation and as the raw material for counterexamples to the famous additivity conjecture. More recently, this perspective has led to methods for encrypting arbitrarily long messages using constant-sized secret keys. I'll sketch the connection and try to recruit an IQC experimentalist to implement this new approach to quantum cryptography.