Neutrino masses and superheavy dark matter in the 3-3-1-1 model

In this work, we interpret the 3-3-1-1 model when the B-L and 3-3-1 breaking scales behave simultaneously as the inflation scale. This setup not only realizes the previously-achieved consequences of inflation and leptogenesis, but also provides new insights in superheavy dark matter and neutrino masses. We argue that the 3-3-1-1 model can incorporate a scalar sextet, which induces both small masses for the neutrinos via a combined type I and II seesaw and large masses for the new neutral fermions. Additionally, all the new particles have the large masses in the inflation scale. The lightest particle among the W-particles that have abnormal (i.e., wrong) B-L number in comparison to those of the standard model particles may be a superheavy dark matter as it is stabilized by the W-parity. The dark matter candidate may be a Majorana fermion, a neutral scalar, or a neutral gauge boson, which was properly created in the early universe due to the gravitational effects on the vacuum or the thermal production after cosmic inflation.Comment: 34 pages, improved with discussions on inflation and reheating as well as presentation, matches published version in EPJ

Thermoelectric effects in correlated quantum dots and molecules

We investigate thermoelectric properties of correlated quantum dots and molecules, described by a single level Anderson model coupled to conduction electron leads, by using Wilson's numerical renormalization group method. In the Kondo regime, the thermopower, $S(T)$, exhibits two sign changes, at temperatures $T=T_{1}$ and $T=T_{2}>T_{1}$. We find that $T_{2}$ is of order the level width $\Gamma$ and $T_{1}> T_{p}\approx T_{K}$, where $T_{p}$ is the position of the Kondo induced peak in the thermopower and $T_{K}$ is the Kondo scale. No sign change is found outside the Kondo regime, or, for weak correlations, making a sign change in $S(T)$ a particularly sensitive signature of strong correlations and Kondo physics. For molecules, we investigate the effect of screening by conduction electrons on the thermoelectric transport. We find that a large screening interaction enhances the figure of merit in the Kondo and mixed valence regimes.Comment: 4 pages, 3 figures; to appear in the Proceedings of the International Conference on Strongly Correlated Electron Systems, Santa Fe 2010; revised version: typos corrected and references update

The 3-3-1 model with A_4 flavor symmetry

We argue that the A_4 symmetry as required by three flavors of fermions may well-embed in the SU(3)_C X SU(3)_L X U(1)_X gauge model. The new neutral fermion singlets as introduced in a canonical seesaw mechanism can be combined with the standard model lepton doublets to perform SU(3)_L triplets. Various leptoscalar multiplets such as singlets, doublets, and triplets as played in the models of A_4 are unified in single SU(3)_L antisextets. As a result, naturally light neutrinos with various kinds of mass hierarchies are obtained as a combination of type I and type II seesaw contributions. The observed neutrino mixing pattern in terms of the Harrison-Perkins-Scott proposal is obtained by enforcing of the A_4 group. The quark masses and Cabibbo-Kobayashi-Maskawa mixing matrix are also discussed. By virtue of very heavy antisextets the nature of the vacuum alignments of scalar fields can be given.Comment: Version published by PR