Tripartite entanglement of an atom in an optical cavity - Tom Harmon

Single-atom cavity quantum electrodynamics (QED) is important at a scientific level as a testbed for atom-field coupling in combined systems and to explore atom-field entanglement, which important for tests of QED and applications to quantum information science. At a technological level, single-atom cavity QED offers the prospect of single-photon sources, quantum memory storage, and quantum computing. The theory of the atom in the cavity is well described by the Jaynes-Cummings model, which treats the atom as an electric dipole interacting with a single mode of the cavity field. However, recent progress with trapping neutral atoms and ions allows quantum features of the motion to arise. The resultant electron-photon-phonon entanglement is especially interesting as a manifestation of tripartite entanglement, which can now be investigated in cavity QED. We are particularly interested in the effect this tripartite entanglement has on the entanglement between the atom-photon system which defines the computational basis. It is shown that tripartite entanglement between all three subsystems comes at the cost of a degredation of the atom-photon entanglement.