793 research outputs found
Dynamical Computation on Coefficients of Electroweak Chiral Lagrangian from One-doublet and Topcolor-assisted Technicolor Models
Based on previous studies deriving the chiral Lagrangian for pseudo scalar
mesons from the first principle of QCD, we derive the electroweak chiral
Lagrangian and build up a formulation for computing its coefficients from
one-doublet technicolor model and a schematic topcolor-assisted technicolor
model. We find that the coefficients of the electroweak chiral Lagrangian for
the topcolor-assisted technicolor model are divided into three parts: direct
TC2 interaction part, TC1 and TC2 induced effective Z' particle contribution
part, and ordinary quarks contribution part. The first two parts are computed
in this paper and we show that the direct TC2 interaction part is the same as
that in the one-doublet technicolor model, while effective Z' contributions are
at least proportional to the p^2 order parameter \beta_1 in the electroweak
chiral Lagrangian and typical features of topcolor-assisted technicolor model
are that it only allows positive T and U parameters and the T parameter varies
in the range 0\sim 1/(25\alpha), the upper bound of T parameter will decrease
as long as Z' mass become large. The S parameter can be either positive or
negative depending on whether the Z' mass is large or small. The Z' mass is
also bounded above and the upper bound depend on value of T parameter. We
obtain the values for all the coefficients of the electroweak chiral Lagrangian
up to order of p^4.Comment: 52 pages, 15 figure
Two-Dimensional Electronic Spectroscopy for Three-Level Atoms with Electromagnetically Induced Transparency
Two-dimensional electronic spectroscopy (2DES) has high spectral resolution
and is a useful tool for studying atom dynamics. In this paper, we apply the
electromagnetically induced transparency (EIT) technique to 2DES in a
three-level atom, and find out that the number of peaks (troughs) will become
more due to the introduction of EIT. Also, the height of the peaks (the depth
of troughs) will change from constant to a damped oscillation. These findings
may help us obtain more information about the dynamics of excited states.Comment: 8 pages, 10 figure
Optimization of SM4 Encryption Algorithm for Power Metering Data Transmission
This study focuses on enhancing the security of the SM4 encryption algorithm for power metering data transmission by employing hybrid algorithms to optimize its substitution box (S-box). A multi-objective fitness function is constructed to evaluate the S-box structure, aiming to identify design solutions that satisfy differential probability, linear probability, and non-linearity balance. To achieve global optimization and local search for the S-box, a hybrid algorithm model that combines genetic algorithm and simulated annealing is introduced. This approach yields significant improvements in optimization effects and increased non-linearity. Experimental results demonstrate that the optimized S-box significantly reduces differential probability and linear probability while increasing non-linearity to 112. Furthermore, a comparison of the ciphertext entropy demonstrates enhanced encryption security with the optimized S-box. This research provides an effective method for improving the performance of the SM4 encryption algorithm
Chaos-assisted two-octave-spanning microcombs
Since its invention, optical frequency comb has revolutionized a broad range of subjects from metrology to spectroscopy. The recent development of microresonator-based frequency combs (microcombs) provides a unique pathway to create frequency comb systems on a chip. Indeed, microcomb-based spectroscopy, ranging, optical synthesizer, telecommunications and astronomical calibrations have been reported recently. Critical to many of the integrated comb systems is the broad coverage of comb spectra. Here, microcombs of more than two-octave span (450 nm to 2,008 nm) is demonstrated through χ^((2)) and χ^((3)) nonlinearities in a deformed silica microcavity. The deformation lifts the circular symmetry and creates chaotic tunneling channels that enable broadband collection of intracavity emission with a single waveguide. Our demonstration introduces a new degree of freedom, cavity deformation, to the microcomb studies, and our microcomb spectral range is useful for applications in optical clock, astronomical calibration and biological imaging
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