128,212 research outputs found
Image Retrieval using Histogram Factorization and Contextual Similarity Learning
Image retrieval has been a top topic in the field of both computer vision and
machine learning for a long time. Content based image retrieval, which tries to
retrieve images from a database visually similar to a query image, has
attracted much attention. Two most important issues of image retrieval are the
representation and ranking of the images. Recently, bag-of-words based method
has shown its power as a representation method. Moreover, nonnegative matrix
factorization is also a popular way to represent the data samples. In addition,
contextual similarity learning has also been studied and proven to be an
effective method for the ranking problem. However, these technologies have
never been used together. In this paper, we developed an effective image
retrieval system by representing each image using the bag-of-words method as
histograms, and then apply the nonnegative matrix factorization to factorize
the histograms, and finally learn the ranking score using the contextual
similarity learning method. The proposed novel system is evaluated on a large
scale image database and the effectiveness is shown.Comment: 4 page
Topological Superfluidity of Spin-Orbit Coupled Bilayer Fermi Gases
Topological superfluid, new quantum matter that possesses gapless exotic
excitations known as Majorana fermions, has attracted extensive attention
recently. These excitations, which can encode topological qubits, could be
crucial ingredients for fault-tolerant quantum computation. However, creating
and manipulating multiple Majorana fermions remain an ongoing challenge.
Loading a topologically protected system in multi-layer structures would be a
natural and simple way to achieve this goal. Here we investigate the system of
bilayer Fermi gases with spin-orbit coupling and show that the topological
condition is significantly influenced by the inter-layer tunneling, yielding
two novel topological phases, which support more Majorana Fermions. We
demonstrate the existence of such novel topological phases and associated
multiple Majorana fermions using bilayer Fermi gases trapped inside a harmonic
potential. This research pave a new way for generating multiple Majorana
fermions and would be a significant step towards topological quantum
computation.Comment: 34 pages, 5 figures, Comments welcom
Eigen-functional bosonization and Eikonal-type equations in one-dimensional strongly correlated electron system
With the eigen-functional bosonization method, we study one-dimensional
strongly correlated electron systems with large momentum ( and/or
) transfer term(s), and demonstrate that this kind of problems ends in
to solve the Eikonal-type equations, and these equations are universal, and
independent of whether or not the system is integrable. In contrast to usual
perturbation theory, this method is valid not only for weak electron
interaction, but also for strong electron interaction. Comparing with exact
solution of some integrable models, it can give correct results in one-loop
approximation. This method can also be used to study electron-phonon
interaction systems, and two coupled spin chain or quantum wire systems.Comment: latex, pages 24, no figure
Nuclear Bag Model and Nuclear Magnetic Moments
In 1991, we proposed a model in which nucleus is treated as a spherical
symmetric MIT bag and nucleon satisfies the MIT bag model boundary condition.
The model was employed to calculate nuclear magnetic moments. The results are
in good agreement with experiment data. Now, we found this model is still
interesting and illuminating.Comment: 5 pages, no figures, Late
Exact expression of the ground state energy of quantum many-particle systems as a functional of the particle density
By introducing a phase field and solving the eigen-functional equation of
particles, we obtain the exact expressions of the ground state energy as a
functional of the particle density for interacting electron/boson systems, and
a two-dimensional electron gas under an external magnetic field, respectively.
With the eigen-functionals of the particles, we can construct the ground state
wave-function of the systems. Moreover, with the expressions of the ground
state energy, we can exactly determine the ground state energy and the ground
state particle density of the systems by taking .Comment: 11 pages, latex fil
Unified theory of quantum many-particle systems
Using eigen-functional bosonization method, we study quantum many-particle
systems, and show that the quantum many-particle problems end in to solve the
differential equation of the phase fields which represent the particle
correlation strength. Thus, the physical properties of these systems are
completely determined by the differential equation of the phase fields. We
mainly focus on the study of D-dimensional electron gas with/without transverse
gauge fields, two-dimensional electron gas under an external magnetic field,
D-dimensional boson systems, a D-dimensional Heisenberg model and a one-band
Hubbard model on a square lattice, and give their exact (accurate for
Heisenberg model) functional expressions of the ground state energy and action,
and the eigen-functional wave functions of the fermions/bosons. With them, we
can calculate a variety of correlation functions of the systems, such as single
particle Green's functions and their ground state wave functions. In present
theoretical framework, we can unifiably represent the Landau Fermi liquid,
non-Fermi liquid () and Tomonaga-Luttinger liquid.Comment: 38 pages, RevTex, no figur
An exact expression of the collective excitation energy gap of fractional quantum Hall effect
We have exactly solved the eigenequation of a two-dimensional Dirac fermion
moving on the surface of a sphere under the influence of a radial magnetic
field B, and obtained an exact expression of the collective excitation energy
gap for the filling factors , m and p are non-zero integers,
which is very well agreement with the computing results.Comment: Revtex, 11 pages, no figure
Influence of gauge fluctuations on fermion pairing order parameter
Using a prototype model, we study the influence of gauge fluctuations on
fermion pairing order parameter which has the gauge symmetry, and demonstrate
that the gauge fluctuations can destroy the long range order of the fermion
pairing order parameter, and make it only have short range correlation. If this
parameter is a superconducting order parameter, we show that the Meissner
effect of the system keeps intact, and the system is in the superconducting
state even though the long range order of the superconducting order parameter
is destroied by the gauge fluctuations. Our calculations support that the
pseudo-gap region of the high Tc cuprate superconductivity is a spin pseudo-gap
region rather than an electron pre-paired region.Comment: Latex, page12, no figure
Normal state property of the t-J model
Using the spin-hole coherent state representation and taking a long range
antiferromagnetic N\`{e}el order as a background of the localized spin degree
part, we have studied the normal state behavior of the t-J model, and shown
that a strongly short-range antiferromagnetic correlation of the localized spin
degree part is responsible for the anomalous non-Korringa-like relaxation
behavior of the planar copper spin, the Korringa-like behavior of the planar
oxygen spin may derive from the charge degree part describing a Zhang-Rice
spin-singlet; The charge degree part feels a strongly staggered magnetic field
induced by this short-range antiferromagnetic correlation as a doping hole
hopping, this staggered magnetic field enforces the charge degrees to have
different responses to external magnetic and electric fields and to show two
relaxation rate behaviors corresponding to the planar resistivity and Hall
angle, respectively. We have found that the temperature dependence of
magnetoresistance is , , near the optimal doping, , in the underdoping region, violating Kohler's rule, the transport
relaxation rate is of the order of , all that are consistent with the
normal state of the cuprate superconductors.Comment: 21 pages, no figures, Revte
Low Temperature Behavior of the Kondo Effect in Tomonaga-Luttinger Liquid
Using the bosonization method, we study the low temperature behavior of the
Kondo effect in the Tomonaga-Luttinger liquid and clearly show that the power
law temperature dependence of the impurity susceptibility is completely
determined by the repulsive electron-electron interaction existing in the total
spin channel and is independent of the electron-electron interaction existing
in the charge channels.Comment: 15 pages, Late
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