AION/Magis

Abstract:

We have investigated the properties of a standing-wave configuration of Gaussian laser beams which gives a linear array of three-dimensional atomic dipole traps. This is achieved by two counter-propagating waves with different beam waists so that at the nodes the field intensity of the standing wave is not completely cancelled at all radial positions across the beam. This creates an intensity dip in both the axial and radial directions that can be used as an atomic trap for blue detuning of the light. We simulated the behaviour of two level atoms in this trap using dressed state Monte-Carlo method and in this paper we show that it gives good trapping when the residual intensity at the bottom of the traps is small. © 1998 Elsevier Science B.V.

Abstract:

We propose a general scheme for constructing models in which the Standard Model (SM) gauge interactions are the mediators of supersymmetry breaking to the fields in the supersymmetric SM, but where the SM gauge groups couple directly to the sector which breaks supersymmetry dynamically. Despite the direct coupling, the models preserve perturbative unification of the SM gauge coupling constants. Furthermore, the supergravity contributions to the squark and slepton masses can be naturally small, typically being much less than 1% of the gauge-mediated (GM) contributions. Both of these goals can be achieved without need of a fine-tuning or a very small coupling constant. This scheme requires run-away directions at the renormalizable level which are only lifted by non-renormalizable terms in the superpotential. To study the proposed scheme in practice, we develop a modified class of models based on SU(N) x SU(N - 1) which allows us to gauge an SU(N - 2) global symmetry. However, we point out a new problem which can exist in models where the dynamical supersymmetry breaking sector and the ordinary sector are directly coupled - the two-loop renormalization group has contributions which can induce negative (mass)(2) for the squarks and sleptons. We clarify the origin of the problem and argue that it is likely to be surmountable. We give a recipe for a successful model. (C) 1998 Published by Elsevier Science B.V.