We study the materials that are composed of metals and insulators.These plasmonic and non-plasmonic materials are ordered in geometric arrangements with dimensions that are fractions of the wavelength of light.A theor...We study the materials that are composed of metals and insulators.These plasmonic and non-plasmonic materials are ordered in geometric arrangements with dimensions that are fractions of the wavelength of light.A theoretical model is developed to simulate the refractive index of these nano-structured electromagnetic materials which support surface plasmon resonances.Factors contributing to the refractive index sensitivity are explored phenomenologically.Particles with size parameters smaller by much less than 1 have optical properties accurately predicted by the quasi-electrostatic theory while particles with larger size parameters necessitate electrodynamics.We simulate a type of refractive index material composed of metal and insulating dielectric nano-spheres,which are able to sustain the propagation of infrared or visible frequency electromagnetic waves known as surface plasmon polaritons.展开更多
We have used the recent effective field theory （EFT） which is constructed from two- and three-nucleon interactions, using minimal substitution in the momentum dependence of these interactions. We present the calcula...We have used the recent effective field theory （EFT） which is constructed from two- and three-nucleon interactions, using minimal substitution in the momentum dependence of these interactions. We present the calcula- tions of the fore-aft asymmetry of γ-rays in the reaction 2H（n,γ）3H which are based on EFT up to next-to-next-to leading order （N2LO）. The results are compared with the recently reported calculations and measurements of the fore-aft asymmetry of T-rays from neutron-deuteron radiative capture. The calculated fore-aft asymmetry of the nd radiative capture process above deuteron breakup threshold is in good agreement with the available experimental data up to 20 MeV.展开更多
We summarize the recent effective field theory （EFT） studies of low-energy electroweak reactions of astrophysical interest, relevant to big-bang nucleosynthesis. The zero energy astrophysical S（0） factor for the t...We summarize the recent effective field theory （EFT） studies of low-energy electroweak reactions of astrophysical interest, relevant to big-bang nucleosynthesis. The zero energy astrophysical S（0） factor for the thermal proton radiative capture by deuteron is calculated with pionless EFT. The astrophysical S（0） factor is accurately determined to be S（0）=0.243 eV·b up to the leading order （LO）. At zero energies, magnetic transition M1 gives the dominant contribution. The M1 amplitude is calculated up to the LO. A good, quantitative agreement between theoretical and experimental results is found for all observables. The demonstrations of cutoff independent calculation have also been presented.展开更多
The astrophysical S-factor of the 4He＋12C radiative capture is calculated in the potential model at the energy range 0.1-2.0 MeV. Radiative capture 12C（α,γ） 16O is extremely relevant for the fate of massive stars...The astrophysical S-factor of the 4He＋12C radiative capture is calculated in the potential model at the energy range 0.1-2.0 MeV. Radiative capture 12C（α,γ） 16O is extremely relevant for the fate of massive stars and determines if the remnant of a supernova explosion becomes a black hole or a neutron star. Because this reaction occurs at low energies, the experimental measurements are very difficult and perhaps impossible. In this paper, radiative capture of the 12C（α,γ） 16O reaction at very low energies is taken as a case study. In comparison with other theoretical methods and available experimental data, good agreement is achieved for the astrophysical S-factor of this process.展开更多
文摘We study the materials that are composed of metals and insulators.These plasmonic and non-plasmonic materials are ordered in geometric arrangements with dimensions that are fractions of the wavelength of light.A theoretical model is developed to simulate the refractive index of these nano-structured electromagnetic materials which support surface plasmon resonances.Factors contributing to the refractive index sensitivity are explored phenomenologically.Particles with size parameters smaller by much less than 1 have optical properties accurately predicted by the quasi-electrostatic theory while particles with larger size parameters necessitate electrodynamics.We simulate a type of refractive index material composed of metal and insulating dielectric nano-spheres,which are able to sustain the propagation of infrared or visible frequency electromagnetic waves known as surface plasmon polaritons.
文摘We have used the recent effective field theory （EFT） which is constructed from two- and three-nucleon interactions, using minimal substitution in the momentum dependence of these interactions. We present the calcula- tions of the fore-aft asymmetry of γ-rays in the reaction 2H（n,γ）3H which are based on EFT up to next-to-next-to leading order （N2LO）. The results are compared with the recently reported calculations and measurements of the fore-aft asymmetry of T-rays from neutron-deuteron radiative capture. The calculated fore-aft asymmetry of the nd radiative capture process above deuteron breakup threshold is in good agreement with the available experimental data up to 20 MeV.
文摘We summarize the recent effective field theory （EFT） studies of low-energy electroweak reactions of astrophysical interest, relevant to big-bang nucleosynthesis. The zero energy astrophysical S（0） factor for the thermal proton radiative capture by deuteron is calculated with pionless EFT. The astrophysical S（0） factor is accurately determined to be S（0）=0.243 eV·b up to the leading order （LO）. At zero energies, magnetic transition M1 gives the dominant contribution. The M1 amplitude is calculated up to the LO. A good, quantitative agreement between theoretical and experimental results is found for all observables. The demonstrations of cutoff independent calculation have also been presented.
文摘The astrophysical S-factor of the 4He＋12C radiative capture is calculated in the potential model at the energy range 0.1-2.0 MeV. Radiative capture 12C（α,γ） 16O is extremely relevant for the fate of massive stars and determines if the remnant of a supernova explosion becomes a black hole or a neutron star. Because this reaction occurs at low energies, the experimental measurements are very difficult and perhaps impossible. In this paper, radiative capture of the 12C（α,γ） 16O reaction at very low energies is taken as a case study. In comparison with other theoretical methods and available experimental data, good agreement is achieved for the astrophysical S-factor of this process.
