How Entangled Is a Many-Electron State?

Abstract

Quantum entanglement is perceived as a resource for quantum communication and information processing and has emerged over the last few years as a major research area in various diverse fields such as physics, mathematics, chemistry, electrical engineering, and computer science [1, 2]. Entanglement in a quantum state is a signature of quantum correlations between different spatial parts of the system. Consider a bipartite system, consisting of two parts A and B, in a pure state. Let $\|A_i>, i=1,N$, be a set of orthogonal basis states for the subsystem A, and similarly $|B_i\rangle, i=1,M$, be an orthogonal basis for the subsystem B. Let the total system be described by a pure state