154 research outputs found
Perturbative Bottom-up Approach for Neutrino Mass Matrix in Light of Large \theta_{13} and Role of Lightest Neutrino Mass
We discuss the role of lightest neutrino mass (m_0) in the neutrino mass
matrix, defined in a flavor basis, through a bottom-up approach using the
current neutrino oscillation data. We find that if m_0 < 10^{-3} eV, then the
deviation \delta M_\nu in the neutrino mass matrix from a tree-level, say
tribimaximal neutrino mass matrix, does not depend on m_0. As a result \delta
M_\nu's are exactly predicted in terms of the experimentally determined
quantities such as solar and atmospheric mass squared differences and the
mixing angles. On the other hand for m_0 \gsim 10^{-3} eV, \delta M_\nu
strongly depends on m_0 and hence can not be determined within the knowledge of
oscillation parameters alone. In this limit, we provide an exponential
parameterization for \delta M_\nu for all values of m_0 such that it can
factorize the m_0 dependency of \delta M_\nu from rest of the oscillation
parameters. This helps us in finding \delta M_\nu as a function of the solar
and atmospheric mass squared differences and the mixing angles for all values
of m_0. We use this information to build up a model of neutrino masses and
mixings in a top-down scenario which can predict large \theta_{13}
perturbatively.Comment: 26 pages, 42 eps figures, revtex (references are added, more
discussions are added in section-III
Automatic CP Invariance and Flavor Symmetry
The approximate conservation of can be naturally understood if it arises
as an automatic symmetry of the renormalizable Lagrangian. We present a
specific realistic example with this feature. In this example, the global
Peccei-Quinn symmetry and gauge symmetries of the model make the renormalizable
Lagrangian invariant but allow non zero hierarchical masses and mixing
among the three generations. The left-right and a horizontal symmetry
is imposed to achieve this. The non-renormalizable interactions invariant under
these symmetries violate whose magnitude can be in the experimentally
required range if is broken at very high, typically, near the grand
unification scale
Doodle to Search: Practical Zero-Shot Sketch-based Image Retrieval
In this paper, we investigate the problem of zero-shot sketch-based image
retrieval (ZS-SBIR), where human sketches are used as queries to conduct
retrieval of photos from unseen categories. We importantly advance prior arts
by proposing a novel ZS-SBIR scenario that represents a firm step forward in
its practical application. The new setting uniquely recognizes two important
yet often neglected challenges of practical ZS-SBIR, (i) the large domain gap
between amateur sketch and photo, and (ii) the necessity for moving towards
large-scale retrieval. We first contribute to the community a novel ZS-SBIR
dataset, QuickDraw-Extended, that consists of 330,000 sketches and 204,000
photos spanning across 110 categories. Highly abstract amateur human sketches
are purposefully sourced to maximize the domain gap, instead of ones included
in existing datasets that can often be semi-photorealistic. We then formulate a
ZS-SBIR framework to jointly model sketches and photos into a common embedding
space. A novel strategy to mine the mutual information among domains is
specifically engineered to alleviate the domain gap. External semantic
knowledge is further embedded to aid semantic transfer. We show that, rather
surprisingly, retrieval performance significantly outperforms that of
state-of-the-art on existing datasets that can already be achieved using a
reduced version of our model. We further demonstrate the superior performance
of our full model by comparing with a number of alternatives on the newly
proposed dataset. The new dataset, plus all training and testing code of our
model, will be publicly released to facilitate future researchComment: Oral paper in CVPR 201
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