4,764 research outputs found
Wave-packet treatment of neutrino oscillations and its implications on determining the neutrino mass hierarchy
We derive the neutrino flavor transition probabilities with the neutrino
treated as a wave packet. The decoherence and dispersion effects from the
wave-packet treatment show up as damping and phase-shifting of the plane-wave
neutrino oscillation patterns. If the energy uncertainty in the initial
neutrino wave packet is larger than around 0.01 of the neutrino energy, the
decoherence and dispersion effects would degrade the sensitivity of reactor
neutrino experiments to mass hierarchy measurement to lower than 3
confidence level
A General SU(2) Formulation for Quantum Searching with Certainty
A general quantum search algorithm with arbitrary unitary transformations and
an arbitrary initial state is considered in this work. To serach a marked state
with certainty, we have derived, using an SU(2) representation: (1) the
matching condition relating the phase rotations in the algorithm, (2) a concise
formula for evaluating the required number of iterations for the search, and
(3) the final state after the search, with a phase angle in its amplitude of
unity modulus. Moreover, the optimal choices and modifications of the phase
angles in the Grover kernel is also studied.Comment: 8 pages, 2 figure
Tensor coupling effects on spin symmetry in anti-Lambda spectrum of hypernuclei
The effects of -tensor coupling on the spin
symmetry of spectra in -nucleus systems have
been studied with the relativistic mean-field theory. Taking
C+ as an example, it is found that the tensor coupling
enlarges the spin-orbit splittings of by an order of magnitude
although its effects on the wave functions of are negligible.
Similar conclusions has been observed in -nucleus of different
mass regions, including O+, Ca+ and
Pb+. It indicates that the spin symmetry in
anti-lambda-nucleus systems is still good irrespective of the tensor coupling.Comment: 12 pages, 3 figures
A General Phase Matching Condition for Quantum Searching Algorithm
A general consideration on the phase rotations in quantum searching algorithm
is taken in this work. As four phase rotations on the initial state, the marked
states, and the states orthogonal to them are taken account, we deduce a phase
matching condition for a successful search. The optimal options for these phase
are obtained consequently.Comment: 3 pages, 3 figure
Federated Learning in Intelligent Transportation Systems: Recent Applications and Open Problems
Intelligent transportation systems (ITSs) have been fueled by the rapid
development of communication technologies, sensor technologies, and the
Internet of Things (IoT). Nonetheless, due to the dynamic characteristics of
the vehicle networks, it is rather challenging to make timely and accurate
decisions of vehicle behaviors. Moreover, in the presence of mobile wireless
communications, the privacy and security of vehicle information are at constant
risk. In this context, a new paradigm is urgently needed for various
applications in dynamic vehicle environments. As a distributed machine learning
technology, federated learning (FL) has received extensive attention due to its
outstanding privacy protection properties and easy scalability. We conduct a
comprehensive survey of the latest developments in FL for ITS. Specifically, we
initially research the prevalent challenges in ITS and elucidate the
motivations for applying FL from various perspectives. Subsequently, we review
existing deployments of FL in ITS across various scenarios, and discuss
specific potential issues in object recognition, traffic management, and
service providing scenarios. Furthermore, we conduct a further analysis of the
new challenges introduced by FL deployment and the inherent limitations that FL
alone cannot fully address, including uneven data distribution, limited storage
and computing power, and potential privacy and security concerns. We then
examine the existing collaborative technologies that can help mitigate these
challenges. Lastly, we discuss the open challenges that remain to be addressed
in applying FL in ITS and propose several future research directions
Photometric Variability in the CSTAR Field: Results From the 2008 Data Set
The Chinese Small Telescope ARray (CSTAR) is the first telescope facility
built at Dome A, Antarctica. During the 2008 observing season, the installation
provided long-baseline and high-cadence photometric observations in the i-band
for 18,145 targets within 20 deg2 CSTAR field around the South Celestial Pole
for the purpose of monitoring the astronomical observing quality of Dome A and
detecting various types of photometric variability. Using sensitive and robust
detection methods, we discover 274 potential variables from this data set, 83
of which are new discoveries. We characterize most of them, providing the
periods, amplitudes and classes of variability. The catalog of all these
variables is presented along with the discussion of their statistical
properties.Comment: 38 pages, 11 figures, 4 tables; Accepted for publication in ApJ
Emerging and reemerging helminthiases and the public health of China.
Despite great strides in their control throughout the People's Republic of China, helminth infections remain an important public health problem. The Institute of Parasitic Diseases of the Chinese Academy of Preventive Medicine, under the guidance of the Chinese Ministry of Health, completed a nationwide survey of more than 1 million people that showed the high prevalence and intensity of intestinal nematode infections; prevalence can sometimes exceed 50% in the Yangtze River valley provinces. Schistosoma japonicum is also a major cause of illness in this region. Attempts to control Chinese helminthic diseases with conventional anthelminthic drugs have been partially thwarted by high posttreatment rates of reinfection. Recently, several new human trematode pathogens have been identified. Novel approaches to chemoprophylaxis and vaccination may alleviate the public health problem caused by Chinese helminths. However, recombinant helminth vaccine development will depend on first cataloguing the extensive genetic diversity of Chinese helminths and candidate vaccine antigens. Evidence from biogeography, genetics, and systematics suggests that the genetic diversification of Chinese helminths and their vectors is an ongoing evolutionary process that began 12 million years ago near the convergence of major Asian river systems. Construction of the Three Gorges Super Dam on the Yangtze River may promote the emergence and reemergence of new helminths and their snail vector
Eclipsing Binaries From the CSTAR Project at Dome A, Antarctica
The Chinese Small Telescope ARray (CSTAR) has observed an area around the
Celestial South Pole at Dome A since 2008. About light curves in the i
band were obtained lasting from March to July, 2008. The photometric precision
achieves about 4 mmag at i = 7.5 and 20 mmag at i = 12 within a 30 s exposure
time. These light curves are analyzed using Lomb--Scargle, Phase Dispersion
Minimization, and Box Least Squares methods to search for periodic signals.
False positives may appear as a variable signature caused by contaminating
stars and the observation mode of CSTAR. Therefore the period and position of
each variable candidate are checked to eliminate false positives. Eclipsing
binaries are removed by visual inspection, frequency spectrum analysis and
locally linear embedding technique. We identify 53 eclipsing binaries in the
field of view of CSTAR, containing 24 detached binaries, 8 semi-detached
binaries, 18 contact binaries, and 3 ellipsoidal variables. To derive the
parameters of these binaries, we use the Eclipsing Binaries via Artificial
Intelligence (EBAI) method. The primary and the secondary eclipse timing
variations (ETVs) for semi-detached and contact systems are analyzed.
Correlated primary and secondary ETVs confirmed by false alarm tests may
indicate an unseen perturbing companion. Through ETV analysis, we identify two
triple systems (CSTAR J084612.64-883342.9 and CSTAR J220502.55-895206.7). The
orbital parameters of the third body in CSTAR J220502.55-895206.7 are derived
using a simple dynamical model.Comment: 41 pages, 12 figures; published online in ApJ
Optical coupling analysis and vibration characterization for packaging of 2 × 2 MEMS vertical torsion mirror switches
ABSTRACT We report optical coupling loss and vibration characterization for packaging of 2x2 vertical torsion mirror switches. The coupling losses of fiber-to-fiber and fiber-lens-lens-fiber are examined in order to design 2x2 MEMS optical switches required for the performance specification. The results indicate that the fiber-lens-lens-fiber configuration provides a over 1 mm working distance of 2.5 dB loss between the lens centers. The fiber-to-fiber only allows 175 xm for the same loss. In addition, the mechanical frequency response of the vertical torsion mirror is experimentally examined by electrostatic excitation. The discrepancy between the calculated and the measured nature frequencies is investigated by the study of the effect of the in-house post processes
Magnetic-coupled electronic landscape in bilayer-distorted titanium-based kagome metals
Quantum materials whose atoms are arranged on a lattice of corner-sharing
triangles, , the kagome lattice, have recently emerged as a
captivating platform for investigating exotic correlated and topological
electronic phenomena. Here, we combine ultra-low temperature angle-resolved
photoemission spectroscopy (ARPES) with scanning tunneling microscopy and
density functional theory calculations to reveal the fascinating electronic
structure of the bilayer-distorted kagome material
TiBi, where stands for Nd and Yb.
Distinct from other kagome materials, TiBi exhibits
two-fold, rather than six-fold, symmetries, stemming from the distorted kagome
lattice, which leads to a unique electronic structure. Combining experiment and
theory we map out the electronic structure and discover double flat bands as
well as multiple van Hove singularities (VHSs), with one VHS exhibiting
higher-order characteristics near the Fermi level. Notably, in the magnetic
version NdTiBi, the ultra-low base temperature ARPES measurements
unveil an unconventional band splitting in the band dispersions which is
induced by the ferromagnetic ordering. These findings reveal the potential of
bilayer-distorted kagome metals TiBi as a promising
platform for exploring novel emergent phases of matter at the intersection of
strong correlation and magnetism
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