388 research outputs found
The Standard Model Gauge Symmetry from Higher-Rank Unified Groups in Grand Gauge-Higgs Unification Models
We study grand unified models in the five-dimensional space-time where the
extra dimension is compactified on . The spontaneous breaking of
unified gauge symmetries is achieved via vacuum expectation values of the
extra-dimensional components of gauge fields. We derive one-loop effective
potentials for the zero modes of the gauge fields in SU(7), SU(8), SO(10), and
models. In each model, the rank of the residual gauge symmetry that
respects the boundary condition imposed at the orbifold fixed points is higher
than that of the standard model. We verify that the residual symmetry is broken
to the standard model gauge symmetry at the global minima of the effective
potential for certain sets of bulk fermion fields in each model.Comment: 34 pages, 1 figure, clarifications added in Sec. 6, published versio
Model Building of Metal Oxide Surfaces and Vibronic Coupling Density as a Reactivity Index: Regioselectivity of CO Adsorption on Ag-loaded GaO
The step-by-step hydrogen-terminated (SSHT) model is proposed as a model for
the surfaces of metal oxides. Using this model, it is found that the vibronic
coupling density (VCD) can be employed as a reactivity index for surface
reactions. As an example, the regioselectivity of CO adsorption on the
Ag-loaded GaO photocatalyst surface is investigated based on VCD
analysis. The cluster model constructed by the SSHT approach reasonably
reflects the electronic structures of the GaO surface. The geometry of
CO adsorbed on the Ag-loaded GaO cluster has a bent structure,
which is favorable for its photocatalytic reduction to CO.Comment: 18 pages, 11 figure
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