21,516 research outputs found
Effective generation of Ising interaction and cluster states in coupled microcavities
We propose a scheme for realizing the Ising spin-spin interaction and atomic
cluster states utilizing trapped atoms in coupled microcavities. It is shown
that the atoms can interact with each other via the exchange of virtual photons
of the cavities. Through suitably tuning the parameters, an effective Ising
spin-spin interaction can be generated in this optical system, which is used to
produce the cluster states. This scheme does not need the preparation of
initial states of atoms and cavity modes, and is insensitive to cavity decay.Comment: 11pages, 2 figures, Revtex
Speed of Sound in the Mass Varying Neutrinos Scenario
We discuss about the speed of sound squared in the Mass Varying Neutrinos
scenario (MaVaNs). Recently, it was argued that the MaVaNs has a catastrophic
instability which is the emergence of an imaginary speed of sound at the
non-relativistic limit of neutrinos. As the result of this instability, the
neutrino-acceleron fluid cannot act as the dark energy. However, it is found
that the speed of sound squared in the neutrino-acceleron fluid could be
positive in our model. We examine the speed of sound in two cases of the scalar
potential. One is the small fractional power-law potential and another is the
logarithmic one. The power-law potential model with the right-handed neutrinos
gives a stable one.Comment: 17 pages, References added, minor modification
Trapped interacting two-component bosons
In this paper we solve one dimensional trapped SU(2) bosons with repulsive
-function interaction by means of Bethe-ansatz method. The features of
ground state and low-lying excited states are studied by numerical and analytic
methods. We show that the ground state is an isospin "ferromagnetic" state
which differs from spin-1/2 fermions system. There exist three quasi-particles
in the excitation spectra, and both holon-antiholon and holon-isospinon
excitations are gapless for large systems. The thermodynamics equilibrium of
the system at finite temperature is studied by thermodynamic Bethe ansatz. The
thermodynamic quantities, such as specific heat etc. are obtained for the case
of strong coupling limit.Comment: 15 pages, 9 figure
Study of the Insulating and Arc-quenching Performance of CO2 and Its Mixtures: A Brief Review
SF6, which is widely used as an insulating or arc-quenching medium in electrical apparatus, has a strong global warming potential. Recently, CO2 and its mixtures attract great attention as a promising alternative gas. This paper presents our calculation and measurement results on the insulating and arc-quenching capabilities of CO2 and its mixtures, including the discharge parameters, arc characteristics, post-arc breakdown properties, and arc-quenching capabilities. On the basis of our study and other published literatures, a discussion of and perspectives on current research and future research directions are presented as well
A novel multi-objective evolutionary algorithm based on space partitioning
To design an e ective multi-objective optimization evolutionary algorithms (MOEA), we need to address the following issues: 1) the sensitivity to the shape of true Pareto front (PF) on decomposition-based MOEAs; 2) the loss of diversity due to paying so much attention to the convergence on domination-based MOEAs; 3) the curse of dimensionality for many-objective optimization problems on grid-based MOEAs. This paper proposes an MOEA based on space partitioning (MOEA-SP) to address the above issues. In MOEA-SP, subspaces, partitioned by a k-dimensional tree (kd-tree), are sorted according to a bi-indicator criterion de ned in this paper. Subspace-oriented and Max-Min selection methods are introduced to increase selection pressure and maintain diversity, respectively. Experimental studies show that MOEA-SP outperforms several compared algorithms on a set of benchmarks
3D tumor localization through real-time volumetric x-ray imaging for lung cancer radiotherapy
Recently we have developed an algorithm for reconstructing volumetric images
and extracting 3D tumor motion information from a single x-ray projection. We
have demonstrated its feasibility using a digital respiratory phantom with
regular breathing patterns. In this work, we present a detailed description and
a comprehensive evaluation of the improved algorithm. The algorithm was
improved by incorporating respiratory motion prediction. The accuracy and
efficiency were then evaluated on 1) a digital respiratory phantom, 2) a
physical respiratory phantom, and 3) five lung cancer patients. These
evaluation cases include both regular and irregular breathing patterns that are
different from the training dataset. For the digital respiratory phantom with
regular and irregular breathing, the average 3D tumor localization error is
less than 1 mm. On an NVIDIA Tesla C1060 GPU card, the average computation time
for 3D tumor localization from each projection ranges between 0.19 and 0.26
seconds, for both regular and irregular breathing, which is about a 10%
improvement over previously reported results. For the physical respiratory
phantom, an average tumor localization error below 1 mm was achieved with an
average computation time of 0.13 and 0.16 seconds on the same GPU card, for
regular and irregular breathing, respectively. For the five lung cancer
patients, the average tumor localization error is below 2 mm in both the axial
and tangential directions. The average computation time on the same GPU card
ranges between 0.26 and 0.34 seconds
Fidelity, dynamic structure factor, and susceptibility in critical phenomena
Motivated by the growing importance of fidelity in quantum critical
phenomena, we establish a general relation between fidelity and structure
factor of the driving term in a Hamiltonian through a newly introduced concept:
fidelity susceptibility. Our discovery, as shown by some examples, facilitates
the evaluation of fidelity in terms of susceptibility using well developed
techniques such as density matrix renormalization group for the ground state,
or Monte Carlo simulations for the states in thermal equilibrium.Comment: 4 pages, 2 figures, final version accepted by PR
The Chinese Hospitality Industry: A perspective article
This paper illustrates the logics shifting in the Chinese hotel industry since1949 and offers a
better understanding of how and why the Chinese hotel industry has evolved into its present situation.
The logic evolution and future trends in this market were also discussed
- …