  Up to now every good quantum error-correcting code discovered has had the
structure of an eigenspace of an Abelian group generated by tensor products of
Pauli matrices; such codes are known as stabilizer or additive codes. In this
letter we present the first example of a code that is better than any code of
this type. It encodes six states in five qubits and can correct the erasure of
any single qubit.
