# Perturbative expansion of entanglement negativity using patterned matrix calculus

Author(s): Jesse C. Cresswell, Ilan Tzitrin, and Aaron Z. Goldberg
Negativity is an entanglement monotone frequently used to quantify entanglement in bipartite states. Because negativity is a nonanalytic function of a density matrix, existing methods used in the physics literature are insufficient to compute its derivatives. To this end we develop techniques in the...
[Phys. Rev. A 99, 012322] Published Mon Jan 14, 2019