Abstract
Abstract
The von Neumann entropy of a k-body-reduced density matrix γ
k
quantifies the entanglement between k quantum particles and the remaining ones. In this paper, we rigorously prove general properties of this entanglement entropy as a function of k; it is concave for all
1
⩽
k
⩽
N
and non-decreasing until the midpoint
k
⩽
⌊
N
/
2
⌋
. The results hold for indistinguishable quantum particles and are independent of the statistics.