1,054 research outputs found
Sudden transition between classical and quantum decoherence in dissipative cavity QED and stationary quantum discord
We investigate the phenomenon of sudden transition between classical and
quantum decoherence in the study of quantum discord for a dissipative cavity
QED system, which consists of two noninteracting two-level atoms, each trapped
in a dissipative cavity. It is found that the quantum discord between two
atoms, which are prepared initially in the X-type quantum states, is not
destroyed by the dissipation of the cavities for a finite time interval and the
stationary quantum discord can arise in the interaction of atoms with cavities
as the time approach to infinite. The transition time is sensitive to the
initial state parameter of the two atoms and the mean photon number of the
coherent field. Interestingly, the quantum discord between the two atoms is
completely unaffected by the dissipation of the cavities if we choose the
suitable value of the ratio, which depends on the decay rate of two cavities
and the atom-field coupling constant.Comment: 8 pages, 14 figure
Cosmological model-independent constraints on spatial curvature from strong gravitational lensing and type Ia supernova observations
Applying the distance sum rule in strong gravitational lensing (SGL) and type
Ia supernova (SN Ia) observations, one can provide an interesting cosmological
model-independent method to determine the cosmic curvature parameter
. In this paper, with the newly compiled data sets including 161
galactic-scale SGL systems and 1048 SN Ia data, we place constraints on
within the framework of three types of lens models extensively used
in SGL studies. Moreover, to investigate the effect of different mass lens
samples on the results, we divide the SGL sample into three sub-samples based
on the center velocity dispersion of intervening galaxies. In the singular
isothermal sphere (SIS) and extended power-law lens models, a flat universe is
supported with the uncertainty about 0.2, while a closed universe is preferred
in the power-law lens model. We find that the choice of lens models and the
classification of SGL data actually can influence the constraints on
significantly.Comment: 10 pages, 4 figures; accepted for publication in The Astrophysical
Journa
Spinor wave equation of photon
In this paper, we give the spinor wave equations of free and unfree photon,
which are the differential equation of space-time one order. For the free
photon, the spinor wave equations are covariant, and the spinors are
corresponding to the the reducibility representations and
of the proper Lorentz group
Transmission Character of General Function Photonic Crystals
In the paper, we present a new general function photonic crystals (GFPCs),
which refractive index of medium is a arbitrary function of space position.
Unlike conventional photonic crystals (PCs), which structure grow from two
mediums and , with different constant refractive indexes and
. Based on Fermat principle, we give the motion equations of light in
one-dimensional GFPCs, and calculate its transfer matrix, which is different
from the conventional PCs. We choose the linearity refractive index function
for two mediums and , and find the transmissivity of one-dimensional
GFPCs can be much larger or smaller than 1 for different slope linearity
refractive index function, which is different from the transmissivity of
conventional PCs (its transmissivity is in the range of 0 and 1). Otherwise, we
study the effect of different incident angles, the number of periods and
optical thickness on the transmissivity, and obtain some new results different
from the conventional PCs.Comment: arXiv admin note: substantial text overlap with arXiv:1207.355
Markov Processes in Blockchain Systems
In this paper, we develop a more general framework of block-structured Markov
processes in the queueing study of blockchain systems, which can provide
analysis both for the stationary performance measures and for the sojourn times
of any transaction and block. Note that an original aim of this paper is to
generalize the two-stage batch-service queueing model studied in Li et al.
\cite{Li:2018} both ``from exponential to phase-type" service times and ``from
Poisson to MAP" transaction arrivals. In general, the MAP transaction arrivals
and the two stages of PH service times make our blockchain queue more suitable
to various practical conditions of blockchain systems with crucial random
factors, for example, the mining processes, the block-generations, the
blockchain-building and so forth. For such a more general blockchain queueing
model, we focus on two basic research aspects: (1) By using the
matrix-geometric solution, we first obtain a sufficient stable condition of the
blockchain system. Then we provide simple expressions for the average number of
transactions in the queueing waiting room, and the average number of
transactions in the block. (2) However, comparing with Li et al.
\cite{Li:2018}, analysis of the transaction-confirmation time becomes very
difficult and challenging due to the complicated blockchain structure. To
overcome the difficulties, we develop a computational technique of the first
passage times by means of both the PH distributions of infinite sizes and the
-factorizations. Finally, we hope that the methodology and results given in
this paper will open a new avenue to queueing analysis of more general
blockchain systems in practice, and can motivate a series of promising future
research on development of lockchain technologies.Comment: 38 pages, 4 figure
The effect of defect layer on transmissivity and light field distribution in general function photonic crystals
We have theoretically investigated a general function photonic crystals
(GFPCs) with defect layer, and choose the line refractive index function for
two mediums and , and analyze the effect of defect layer's position,
refractive indexes and period numbers on the transmission intensity and the
electric field distribution. We obtain some new characters that are different
from the conventional PCs, which should be helpful in the design of photonic
crystals.Comment: arXiv admin note: substantial text overlap with arXiv:1207.3556,
arXiv:1205.1178, arXiv:1212.079
A Survey on Truth Discovery
Thanks to information explosion, data for the objects of interest can be
collected from increasingly more sources. However, for the same object, there
usually exist conflicts among the collected multi-source information. To tackle
this challenge, truth discovery, which integrates multi-source noisy
information by estimating the reliability of each source, has emerged as a hot
topic. Several truth discovery methods have been proposed for various
scenarios, and they have been successfully applied in diverse application
domains. In this survey, we focus on providing a comprehensive overview of
truth discovery methods, and summarizing them from different aspects. We also
discuss some future directions of truth discovery research. We hope that this
survey will promote a better understanding of the current progress on truth
discovery, and offer some guidelines on how to apply these approaches in
application domains
Non-relativistic quantum theory at finite temperature
We propose the non-relativistic finite temperature quantum wave equations for
a single particle and multiple particles. We give the relation between energy
eigenvalues, eigenfunctions, transition frequency and temperature, and obtain
some results: (1) when the degeneracies of two energy levels are same, the
transition frequency between the two energy levels is unchanged when the
temperature is changed. (2) When the degeneracies of two energy levels are
different, the variance of transition frequency at two energy levels is direct
proportion to temperature difference.Comment: arXiv admin note: text overlap with arXiv:hep-th/0506258 by other
authors without attributio
Full Quantum Theory of Double-slit Diffraction
In this paper, we apply the full new method of quantum theory to study the
double-slit diffraction of molecules. We calculate the double-slit
wave functions of molecules by Schr\"{o}dinger equation, and
calculate the diffraction wave function behind the slits with the Feynman path
integral quantum theory, and then give the relation between the diffraction
intensity of double-slit and diffraction pattern position. We compare the
calculation results with two different double-slit diffraction experiments.
When the decoherence effects are considered, the calculation results are in
good agreement with the two experimental data
Quantum theory of light double-slit diffraction
In this paper, we study the light double-slit diffraction experiment with
quantum theory approach. Firstly, we calculate the light wave function in slits
by quantum theory of photon. Secondly, we calculate the diffraction wave
function with Kirchhoff's law. Thirdly, we give the diffraction intensity of
light double-slit diffraction, which is proportional to the square of
diffraction wave function. Finally, we compare calculation result of quantum
theory and classical electromagnetic theory with the experimental data. We find
the quantum calculate result is accordance with the experiment data, and the
classical calculation result with certain deviation. So, the quantum theory is
more accurately approach for studying light diffraction
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