5,780 research outputs found
Quantum logical gates with four-level SQUIDs coupled to a superconducting resonator
We propose a way for realizing a two-qubit controlled phase gate with
superconducting quantum interference devices (SQUIDs) coupled to a
superconducting resonator. In this proposal, the two lowest levels of each
SQUID serve as the logical states and two intermediate levels of each SQUID are
used for the gate realization. We show that neither adjustment of SQUID level
spacings during the gate operation nor uniformity in SQUID parameters is
required by this proposal. In addition, this proposal does not require the
adiabatic passage or a second-order detuning and thus the gate is much faster.Comment: 6 pages, 3 figure
Dependence of the decoherence of polarization states in phase-damping channels on the frequency spectrum envelope of photons
We consider the decoherence of photons suffering in phase-damping channels.
By exploring the evolutions of single-photon polarization states and two-photon
polarization-entangled states, we find that different frequency spectrum
envelopes of photons induce different decoherence processes. A white frequency
spectrum can lead the decoherence to an ideal Markovian process. Some color
frequency spectrums can induce asymptotical decoherence, while, some other
color frequency spectrums can make coherence vanish periodically with variable
revival amplitudes. These behaviors result from the non-Markovian effects on
the decoherence process, which may give rise to a revival of coherence after
complete decoherence.Comment: 7 pages, 4 figures, new results added, replaced by accepted versio
Analogue to multiple electromagnetically induced transparency in all-optical drop-filter systems
We theoretically study a parallel optical configuration which includes N
periodically coupled whispering-gallery-mode resonators. The model shows an
obvious effect which has a direct analogy with the phenomenon of multiple
electromagnetically induced transparency in quantum systems. The numerical
simulations illuminate that the frequency transparency windows are sharp and
highly transparent. We also briefly discuss the experimental feasibility of the
current scheme in two practical systems, microrings and microdisks.Comment: 4 pages, 4 figure
The Online Data Quality Monitoring System at BESIII
The online Data Quality Monitoring (DQM) plays an important role in the data
taking process of HEP experiments. BESIII DQM samples data from online data
flow, reconstructs them with offline reconstruction software, and automatically
analyzes the reconstructed data with user-defined algorithms. The DQM software
is a scalable distributed system. The monitored results are gathered and
displayed in various formats, which provides the shifter with current run
information that can be used to find problems early. This paper gives an
overview of DQM system at BESIII.Comment: Already submit to Chinese Physics
Topological Edge Plasmon Modes between Diatomic Chains of Nanoparticles
We study the topological edge plasmon modes between two "diatomic" chains of
identical plasmonic nanoparticles. Zak phase for longitudinal plasmon modes in
each chain is calculated analytically by solutions of macroscopic Maxwell's
equations for particles in quasi-static dipole approximation. This
approximation provides a direct analogy with the Su-Schrieffer-Heeger model
such that the eigenvalue is mapped to the frequency dependent
inverse-polarizability of the nanoparticles. The edge state frequency is found
to be the same as the single-particle resonance frequency, which is insensitive
to the separation distances within a unit cell. Finally, full electrodynamic
simulations with realistic parameters suggest that the edge plasmon mode can be
realized through near-field optical spectroscopy.Comment: 7 pages, 6 figure
Calculations of Resonance Coupling Constants in the Scalar Sector of the ENJL Model
We derive the scalar resonance coupling constants of resonance chiral theory
from the Extended Nambu Jona-Lasinio model by using heat-kernel expansion.Comment: 7 page
The prevalence of autism spectrum disorders in China: A comprehensive meta-analysis
There are conflicting prevalence estimates of autism spectrum disorders (ASDs) in mainland China (China thereafter). This study is a comprehensive meta-analysis of the pooled prevalence of ASDs in the general population in China. Study investigators independently conducted a systematic literature search of the following databases: PubMed, EMBASE, PsycINFO, China National Knowledge Infrastructure, Chinese biomedical literature service system, and Wan Fang. Studies reporting prevalence of ASDs and autism in Chinese population were identified and analysed using the Comprehensive Meta-Analysis program with the random effects model. Forty-four studies were included in the meta-analysis comprising 2,337,321 subjects of whom 46.66 % were females. The mean age of subjects ranged from 1.6 to 8 years. Based on diagnostic criteria the pooled prevalence of ASDs was 39.23 per 10,000 (95% CI: 28.44-50.03 per 10,000, I2=89.2%); specifically, the prevalence of autism was 10.18 per 10,000 (95% CI: 8.46-11.89 per 10,000, I2=92.5%). Subgroup analyses revealed significant difference in the prevalence of ASDs between genders (72.77 per 10,000 in males vs. 16.45 per 10,000 in females). In conclusion, the prevalence of ASDs and autism in China was found generally lower than those reported in other countries. Further studies are needed to clarify the variation in prevalence
Variable weight neural networks and their applications on material surface and epilepsy seizure phase classifications
This paper presents a novel neural network having variable weights, which is able to improve its learning and generalization capabilities, to deal with classification problems. The variable weight neural network (VWNN) allows its weights to be changed in operation according to the characteristic of the network inputs so that it demonstrates the ability to adapt to different characteristics of input data resulting in better performance compared with ordinary neural networks with fixed weights. The effectiveness of the VWNN is tested with the consideration of two real-life applications. The first application is on the classification of materials using the data collected by a robot finger with tactile sensors sliding along the surface of a given material. The second application considers the classification of seizure phases of epilepsy (seizure-free, pre-seizure and seizure phases) using real clinical data. Comparisons are performed with some traditional classification methods including neural network, k-nearest neighbors and naive Bayes classification techniques. It is shown that the VWNN classifier outperforms the traditional methods in terms of classification accuracy and robustness property when input datais contaminated by noise
Effect of pinning and driving force on the metastability effects in weakly pinned superconductors and the determination of spinodal line pertaining to order-disorder transition
We explore the effect of varying drive on metastability features exhibited by
the vortex matter in single crystals of 2H-NbSe and CeRu with varying
degree of random pinning. An optimal balance between the pinning and driving
force is needed to view the metastability effects in typically weakly pinned
specimen of low temperature superconductors. As one uses samples with larger
pinning in order to differentiate the response of different metastable vortex
states, one encounters a new phenomena, viz., the second magnetization peak
(SMP) anomaly prior to the PE. Interplay between the path dependence in the
critical current density and the non-linearity in the electromagnetic response
determine the metastability effects seen in first and the third harmonic
response of the ac susceptibility across the temperature regions of the SMP and
the PE. The limiting temperature above which metastability effects cease can be
conveniently located in the third harmonic data, and the observed behavior can
be rationalized within the Beans Critical State model. A vortex phase diagram
showing the different vortex phases for a typically weakly pinned specimen has
been constructed via the ac susceptibility data in a crystal of 2H-NbSe
which shows the SMP and the PE anomalies. The phase space of coexisting weaker
and stronger pinned regions has been identified. It can be bifurcated into two
parts, where the order and disorder dominate, respectively. The former part
continuously connects to the reentrant disordered vortex phase pertaining to
the small bundle pinning regime, where the vortices are far apart, interaction
effects are weak and the polycrystalline form of flux line lattice prevails.Comment: Submitted to the Special Volume on Vortex State Studies, Pramana J.
Phy
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