Entanglement of random subspaces via the Hastings bound

Recently, Hastings ['A counterexample to additivity of minimum output entropy', Nat. Phys. 5, 255 (2009); e-print arXiv:0809.3972v3] proved the existence of random unitary channels, which violate the additivity conjecture. In this paper, we use Hastings' method to derive new bounds for the entanglement of random subspaces of bipartite systems. As an application we use these bounds to prove the existence of nonunital channels, which violate additivity of minimal output entropy.