Orbital Entanglement and Violation of Bell Inequalities in Mesosopic Conductors

We investigate the generation and detection of orbitally entangled states in electrical conductors. Orbital entanglement might be easier to detect than spin entanglement. We discuss a normal-superconducting hybrid structure in which entanglement is between pairs of electrons emitted at two different contacts. We also discuss a purely normal structure in which entanglement occurs in the form of electron-hole pairs or through post-selection on an unentangled many-electron state. A violation of a Bell inequality is used as an objective entanglement test.