The bound of entanglement of superpositions with more than two components
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, 210093, P.R. China
Corresponding author: a email@example.com
Revised: 21 January 2008
Published online: 20 February 2008
A bipartite quantum state (for two systems in any dimensions) can be decomposed as a superposition of many components. For a superposition of more than two components we prove that there is a bound of the entanglement of the superposition state which can be expressed according to entanglements of its component states. Especially, if the component states are mutually bi-orthogonal, the entanglement of the superposition state can be exactly given in terms of the entanglements of the states being superposed.
PACS: 03.67.-a – Quantum information / 03.65.Ta – Foundations of quantum mechanics; measurement theory / 03.65.Ud – Entanglement and quantum nonlocality (e.g. EPR paradox, Bell's inequalities, GHZ states, etc.)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2008