Entanglement for a two-parameter class of states in 2 nquantum system
Dong Pyo Chi, Soojoon Lee · Journal of Physics A Mathematical and General · 2003
We exhibit a two-parameter class of states ρ (α,γ) in a 2 ⊗ n quantum system for n ⩾ 3, which can be obtained from an arbitrary state by means of local quantum operations and classical communication, and which are invariant under all bilateral operations on a 2 ⊗ n quantum system. We calculate the negativity of ρ (α,γ) , and a lower bound and a tight upper bound on its entanglement of formation. It follows from this calculation that the entanglement of formation of ρ (α,γ) cannot exceed its negativity.