Optically induced entanglement of excitons in a single quantum dot

Optically induced entanglement is identified by the spectrum of the phase-s ensitive homodyne-detected coherent nonlinear optical response in a single gallium arsenide quantum dot. The electron-hole entanglement involves two m agneto-excitonic states differing in transition energy and polarization. Th e strong coupling needed for entanglement is provided through the Coulomb i nteraction involving the electrons and holes. The result presents a first s tep toward the optical realization of quantum Logic operations using two or more quantum dots.