title: Decoherence-free generation of many-particle entanglement by adiabatic ground-state transitions.
abstract: We discuss a decoherence insensitive method to create many-particle entanglement in a spin system with controllable collective interactions and propose an implementation in an ion trap. An adiabatic change of parameters allows a transfer from separable to a large variety of entangled eigenstates. We show that the Hamiltonian can have a supersymmetry permitting an explicit construction of the ground state at all times. Of particular interest is a transition in a nondegenerate ground state with a finite energy gap since here the influence of collective as well as individual decoherence mechanisms is substantially reduced. A lower bound for the energy gap is given.
authors.affiliation: Fachbereich Physik, Universität Kaiserslautern, 67653 Kaiserslautern, Germany.
authors.forename: R G
authors.initials: RG
authors.lastname: Unanyan
authors.forename: M
authors.initials: M
authors.lastname: Fleischhauer