  In this note we give sharp estimates on the volume of the set of separable
states on N qubits. In particular, the magnitude of the "effective radius" of
that set in the sense of volume is determined up to a factor which is a (small)
power of N, and thus precisely on the scale of powers of its dimension.
Additionally, one of the appendices contains sharp estimates (by known methods)
for the expected values of norms of the GUE random matrices. We employ standard
tools of classical convexity, high-dimensional probability and geometry of
Banach spaces.
