title: Spin filtering and entanglement swapping through coherent evolution of a single quantum dot.
abstract: We exploit the nondissipative dynamics of a pair of electrons in a large square quantum dot to perform singlet-triplet spin measurement through a single charge detection and show how this may be used for entanglement swapping and teleportation. The method is also used to generate the Affleck-Kennedy-Lieb-Tasaki ground state, a further resource for quantum computation. We justify, and derive analytic results for, an effective charge-spin Hamiltonian which is valid over a wide range of parameters and agrees well with exact numerical results of a realistic effective-mass model. Our analysis also indicates that the method is robust to the choice of dot-size and initialization errors, as well as decoherence.
authors.affiliation: Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: Jose Garcia
authors.initials: JG
authors.lastname: Coello
authors.forename: Abolfazl
authors.initials: A
authors.lastname: Bayat
authors.forename: Sougato
authors.initials: S
authors.lastname: Bose
authors.forename: John H
authors.initials: JH
authors.lastname: Jefferson
authors.forename: Charles E
authors.initials: CE
authors.lastname: Creffield