2,842 research outputs found
Parton Distributions from Boosted Fields in the Coulomb Gauge
We propose a new method to calculate parton distribution functions (PDFs)
from correlations of boosted quarks and gluons in the Coulomb gauge. Compared
to the widely used quasi-PDFs defined from gauge-invariant Wilson-line
operators, such correlations offer advantages including absence of linear power
divergence, enhanced long-range precision, and accessibility to larger off-axis
momenta. We verify the validity of this method at next-to-leading order in
perturbation theory and use it to calculate the pion valence quark PDF on a
lattice with spacing fm and valence pion mass MeV. Our
result agrees with that from the gauge-invariant quasi-PDF at similar
precision, achieved with only half the computational cost through a large
off-axis momentum GeV. This opens the door to a more
efficient way to calculate parton physics on the lattice.Comment: 5 pages, 4 figures, and the appendi
Radio Polarization of BL Lacertae objects
In this paper, using the database of the university of Michigan Radio
Astronomy Observatory (UMRAO) at three (4.8 GHz, 8 GHZ, and 14.5 GHz) radio
frequencies, we studied the polarization properties for 47 BL Lacertae
objects(38 radio selected BL Lacertae objects, 7 X-ray selected BL Lacertae,
and two inter-middle objects (Mkn 421 and Mkn 501), and found that (1) The
polarizations at higher radio frequency is higher than those at lower
frequency, (2) The variability of polarization at higher radio frequency is
higher than those at lower frequency, (3) The polarization is correlated with
the radio spectral index, and (4) The polarization is correlated with
core-dominance parameter for those objects with known core-dominance parameters
suggesting that the relativistic beaming could explain the polarization
characteristic of BL Lacs.Comment: 5 pages, 3 figures, 1 table. PASJ, in pres
2-[5-(1,3-Benzodioxol-5-yl)-3-ferrocenyl-4,5-dihydro-1H-pyrazol-1-yl]-4-phenyl-1,3-thiazole
In the title compound, [Fe(C5H5)(C24H18N3O2S)], the pyrazoline ring adopts a twist conformation. The thiazole ring forms dihedral angles of 83.7 (2) and 34.4 (2)° with the benzene ring of the benzodioxole ring and the fused phenyl ring, respectively. The molecular conformation is stabilized by an intramolecular C—H⋯π interaction. The crystal packing features intermolecular C—H⋯N, C—H⋯O hydrogen bonds and weak C—H⋯π interactions
Research on the compression algorithm of the infrared thermal image sequence based on differential evolution and double exponential decay model.
This paper has proposed a new thermal wave image sequence compression algorithm by combining double exponential decay fitting model and differential evolution algorithm. This study benchmarked fitting compression results and precision of the proposed method was benchmarked to that of the traditional methods via experiment; it investigated the fitting compression performance under the long time series and improved model and validated the algorithm by practical thermal image sequence compression and reconstruction. The results show that the proposed algorithm is a fast and highly precise infrared image data processing method
Two-component polariton condensate in optical microcavity
We present a scheme for engineering the extended two-component Bose-Hubbard
model using polariton condensate supported by optical microcavity. Compared to
the usual two-component Bose-Hubbard model with only Kerr nonlinearity, our
model includes a nonlinear tunneling term which depends on the number
difference of the particle in the two modes. In the mean field treatment, this
model is an analog to a nonrigid pendulum with a variable pendulum length whose
sign can be also changed. We study the dynamic and ground state properties of
this model and show that there exists a first-order phase transition as the
strength of the nonlinear tunneling rate is varied. Furthermore, we propose a
scheme to obtain the polariton condensate wave function.Comment: 9 pages, 8 figure
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