27,959 research outputs found
Semidirect Product Groups, Vacuum Alignment and Tribimaximal Neutrino Mixing
The neutrino oscillation data are in very good agreement with the
tribimaximal mixing pattern: \sin^2\theta_{23}=1/2, \sin^2\theta_{12}=1/3, and
\sin^2\theta_{13}=0. Attempts to generate this pattern based on finite family
symmetry groups typically assume that the family symmetry is broken to
different subgroups in the charged lepton and the neutrino mass matrices. This
leads to a technical problem, where the cross-couplings between the Higgs
fields responsible for the two symmetry breaking chains force their vacuum
expectation values to align, upsetting the desired breaking pattern. Here, we
present a class of models based on the semidirect product group (S_3)^4 \rtimes
A_4, where the lepton families belong to representations which are not
faithful. In effect, the Higgs sector knows about the full symmetry while the
lepton sector knows only about the A_4 factor group. This can solve the
alignment problem without altering the desired properties of the family
symmetry. Inclusion of quarks into the framework is straightforward, and leads
to small and arbitrary CKM mixing angles. Supersymmetry is not essential for
our proposal, but the model presented is easily supersymmetrized, in which case
the same family symmetry solves the SUSY flavor problem.Comment: Typos fixed, 26 pages in LaTe
Entropy production in thermostats II
We show that an arbitrary Anosov Gaussian thermostat close to equilibrium has
positive entropy poduction unless the external field has a global
potential. The configuration space is allowed to have any dimension and
magnetic forces are also allowed. We also show the following non-perturbative
result. Suppose a Gaussian thermostat satisfies
for every 2-plane , where
is the sectional curvature of the associated Weyl connection and
is the orthogonal projection of onto . Then the
entropy production of any SRB measure is positive unless has a global
potential. A related non-perturbative result is also obtained for certain
generalized thermostats on surfaces
An Analysis of Theme and Rheme Used in the Five-star Hotels' Web Sites in Surabaya
The study done by the writer observes the themes and rhemes used in the five-star hotels' web sites in Surabaya. It includes the types of themes and the notions of subject which are under the Systemic Functional Grammar (SFG) proposed by Halliday and Matthiessen (2004). In addition, the data of the study are in the form of text and taken from seven Surabaya five-star hotels' web sites. The writer also used a descriptive qualitative approach in analyzing the 155 data. From the analysis, it is found the two kinds of structure of theme and rheme used by the hotels in their web sites. The hotels also used three types of theme which are simple theme, clause as a theme, and thematic equative. In terms of the subjects (psychological subject, grammatical subject, and logical subject), the hotels are able to fulfill either one, two, or three notions of subject
Anderson localization of pairs in bichromatic optical lattices
We investigate the formation of bound states made of two interacting atoms
moving in a one dimensional (1D) quasi-periodic optical lattice. We derive the
quantum phase diagram for Anderson localization of both attractively and
repulsively bound pairs. We calculate the pair binding energy and show
analytically that its behavior as a function of the interaction strength
depends crucially on the nature -extended, multi-fractal, localized- of the
single-particle atomic states. Experimental implications of our results are
discussed.Comment: final revised version with more explanations, 4 pages, 3 figure
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