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We show that a pure gauge theory in higher dimensions may lead to an effective lower-dimensional theory with massive vector field, broken gauge symmetry and no fundamental Higgs boson. The mechanism we propose employs the localization of a vector field on ...
Scherk-Schwarz gauge symmetry breaking of a D-dimensional field theory model compactified on a circle is analyzed. It is explicitly shown that forbidden couplings in the,unbroken theory appear in the one-loop effective action only in a nonlocal way, implyi ...
We study examples of chiral four-dimensional IIB orientifolds with Scherk-Schwarz supersymmetry breaking, based on freely acting orbifolds. We construct a new Z(3) x Z(3)' model, containing only D9-branes, and rederive from a more geometric perspective the ...
Using a first-principles density functional approach, we calculate the first-order Raman intensities of alpha -quartz. The dynamical charge tensors, vibrational frequencies and eigenmodes, and polarizability tensors are obtained within a perturbational app ...
Due to the ubiquitous presence of a Berry phase, in most cases of dynamical Jahn-Teller systems the symmetry of the vibronic ground state is the same as that of the original degenerate electronic state; As a single exception, the linear H x h icosahedral m ...
We study higher-dimensional non-supersymmetric orbifold models where the Higgs field is identified with some internal component of a gauge field. We address two important and related issues that constitute severe obstacles towards model building within thi ...
The increasing use of contrast agents in magnetic resonance imaging (MRI) for medical diagnosis is due to the ability, called relaxivity, of these paramagnetic compounds to accelerate the relaxation of the surrounding water proton spins. A new classical fo ...
In a molecular semiconductor, a charged molecule experiences a lattice relaxation which reorganizes it into a cation or an anion-radical. This species is not, in general, a polaron. By using calculations of the geometry and the electronic structure both ab ...
We study the consistency of orbifold field theories and clarify to what extent the condition of having an anomaly-free spectrum of zero modes is sufficient to guarantee it. Preservation of gauge invariance at the quantum level is possible, although at the ...
The role of the confinement potential symmetry on the electronic and optical properties of quantum mires is systematically studied. In a wide class of quantum mires with mirror symmetry we evidence a new set of optical transitions resulting both from band ...