A perturbative approach to a class of Fokker-Planck equations

In this paper we present a direct perturbative method to solving certain Fokker-Planck equations, which have constant diffusion coefficients and some small parameters in the drift coefficients. The method makes use of the connection between the Fokker-Planck and Schr\"odinger equations. Two examples are used to illustrate the method. In the first example the drift coefficient depends only on time but not on space. In the second example we consider the Uhlenbeck-Ornstein process with a small drift coefficient. These examples show that the such perturbative approach can be a useful tool to obtain approximate solutions of Fokker-Planck equations with constant diffusion coefficients.Comment: 5 pages, no figure

B→KB\to K Transition Form Factor with Tensor Current within the kTk_T Factorization Approach

In the paper, we apply the $k_T$ factorization approach to deal with the $B\to K$ transition form factor with tensor current in the large recoil regions. Main uncertainties for the estimation are discussed and we obtain $F_T^{B\to K}(0)=0.25\pm0.01\pm0.02$, where the first error is caused by the uncertainties from the pionic wave functions and the second is from that of the B-meson wave functions. This result is consistent with the light-cone sum rule results obtained in the literature.Comment: 8 pages, 4 figures, references adde

Majorana versus Dirac mass from holomorphic supersymmetric Nambu-Jona-Lasinio Model

We study the theoretical features in relation to dynamical mass generation and symmetry breaking for the recently proposed holomorphic supersymmetric Nambu--Jona-Lasinio model. The basic model has two different chiral superfields (multiplets) with a strongly coupled dimension five four-superfield interaction. In addition to the possibility of generation of Dirac mass between the pair established earlier, we show here the new option of generation of Majorana masses for each chiral superfield. We also give a first look at what condition may prefer Dirac over Majorana mass, illustrating that a split in the soft supersymmetry breaking masses is crucial. In particular, in the limit where one of the soft masses vanish, we show that generation of the Majorana mass is no longer an option, while the Dirac mass generation survives well. The latter is sensitive mostly to the average of the two soft masses. The result has positive implication on the application of the model framework towards dynamical electroweak symmetry breaking with Higgs superfields as composites.Comment: 15 pages, 1 figure. Revised version matches the accepted one for publication in Phy.Rev.D Journa

Near-Field Radiative Heat Transfer Between Metasurfaces: A Full-Wave Study Based on 2D Grooved Metal Plates

Metamaterials possess artificial bulk and surface electromagnetic states. Tamed dispersion properties of surface waves allow one to achieve controllable super-Planckian radiative heat transfer (RHT) process between two closely spaced objects. We numerically demonstrate enhanced RHT between two 2D grooved metal plates by a full-wave scattering approach. The enhancement originates from both transverse magnetic spoof surface plasmon polaritons and a series of transverse electric bonding- and anti-bonding waveguide modes at surfaces. The RHT spectrum is frequency-selective, and highly geometrically tailorable. Our simulation also reveals thermally excited non-resonant surface waves in constituent materials can play a prevailing role for RHT at an extremely small separation between two plates, rendering metamaterial modes insignificant for the energy transfer process

Toxicity of G-P Compound Bioinsecticide to Aphids and Their Natural Enemies in Soybean Fields

The results of both laboratory and field tests on the toxicity of GP compound bioinsecticide to aphids and their natural enemies in soybean fields were reported in this paper. In the laboratory tests, aphid mortalities of 77.3% to 80.5% were achieved 24 hours after the spraying of 1 to 400 diluted G-P bioinsecticide; and the mortalities reached 91.3% to 96.1% 48 hours after the spraying. The control effects of this bioinsecticide on aphids in field test were 91.0%, which was similar to the results of 1 to 1000 diluted of 40% omethoate. The G-P bioinsecticide showed low toxicity to the natural enemies of aphids.Originating text in Chinese.Citation: Dai, Mei Xue, Zu, Ai Min. (1997). Toxicity of G-P Compound Bioinsecticide to Aphids and Their Natural Enemies in Soybean Fields. Natural Enemies of Insects, 19(2), 49-54