2005/06/17 by Kiran K. Manne, Carlton M. Caves, Manne, Kiran K. +1 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #Quantum Physics (quant-ph) #quant-ph
paper · pdf · doi:10.48550/arxiv.quant-ph/0506151
15 pages, 2 figures; slight change in introduction, additional references
arxiv created 2005/06/30 · arxiv updated 2009/12/01
Computing the entanglement of formation of a bipartite state is generally difficult, but special symmetries of a state can simplify the problem. For instance, this allows one to determine the entanglement of formation of Werner states and isotropic states. We consider a slightly more general class of states, rotationally symmetric states, also known as SU(2)-invariant states. These states are invariant under global rotations of both subsystems, and one can examine entanglement in cases where the subsystems have different dimensions. We derive an analytic expression for the entanglement of formation of rotationally symmetric states of a spin-j particle and a spin-1\over2 particle. We also give expressions for the I-concurrence, I-tangle, and convex-roof-extended negativity.