Date: Friday 16 September 2011, 4:30pm Location: Elizabethtown College, Esbenshade Hall Room 382 Speaker: David Lyons, Lebanon Valley College Title: Classifying entanglement for symmetric states of $n$ quantum bits Abstract. We consider the problem of entanglement classification for multiqubit quantum states, interest in which is motivated by spectacular applications to computation and communication in addition to new insight into foundational questions in quantum mechanics. In mathematical terms, the question is about classifying orbits of finite dimensional Lie group actions on finite dimensional vector spaces. We discuss why this is interesting, why this is hard, and recent results for the special case of states that remain invariant under permutation of qubits. We present an analysis based on the elegant geometric picture of symmetric states called the Majorana representation.