In medium T matrix for neutron matter

We calculate the equation of state of pure neutron matter, comparing the G-matrix calculation with the in-medium T-matrix result. At low densities, we obtain similar energies per nucleon, however some differences appear at higher densities. We use the self-consistent spectral functions from the T-matrix approach to calculate the 1S0 superfluid gap including self-energy effects. We find a reduction of the superfluid gap by 30%

Representations for Three-Body T-Matrix on Unphysical Sheets

Explicit representations are formulated for the Faddeev components of three-body T-matrix continued analytically on unphysical sheets of the energy Riemann surface. According to the representations, the T-matrix on unphysical sheets is obviously expressed in terms of its components taken on the physical sheet only. The representations for T-matrix are used then to construct similar representations for analytical continuation of three-body scattering matrices and resolvent. Domains on unphysical sheets are described where the representations obtained can be applied.Comment: 123 Kb; LaTeX; Journal-ref was added (the title changed in the journal

Calculation of the T-matrix: general considerations and application of the point-matching method

The T-matrix method is widely used for the calculation of scattering by particles of sizes on the order of the illuminating wavelength. Although the extended boundary condition method (EBCM) is the most commonly used technique for calculating the T-matrix, a variety of methods can be used. We consider some general principles of calculating T-matrices, and apply the point-matching method to calculate the T-matrix for particles devoid of symmetry. This method avoids the time-consuming surface integrals required by the EBCM.Comment: 10 pages. 2 figures, 1 tabl

Energy Dependence of the NN t-matrix in the Optical Potential for Elastic Nucleon-Nucleus Scattering

The influence of the energy dependence of the free NN t-matrix on the optical potential of nucleon-nucleus elastic scattering is investigated within the context of a full-folding model based on the impulse approximation. The treatment of the pole structure of the NN t-matrix, which has to be taken into account when integrating to negative energies is described in detail. We calculate proton-nucleus elastic scattering observables for $^{16}$O, $^{40}$Ca, and $^{208}$Pb between 65 and 200 MeV laboratory energy and study the effect of the energy dependence of the NN t-matrix. We compare this result with experiment and with calculations where the center-of-mass energy of the NN t-matrix is fixed at half the projectile energy. It is found that around 200 MeV the fixed energy approximation is a very good representation of the full calculation, however deviations occur when going to lower energies (65 MeV).Comment: 11 pages (revtex), 6 postscript figure

Variational solution of the T-matrix integral equation

We present a variational solution of the T-matrix integral equation within a local approximation. This solution provides a simple form for the T matrix similar to Hubbard models but with the local interaction depending on momentum and frequency. By examining the ladder diagrams for irreducible polarizability, a connection between this interaction and the local-field factor is established. Based on the obtained solution, a form for the T-matrix contribution to the electron self-energy in addition to the GW term is proposed. In the case of the electron-hole multiple scattering, this form allows one to avoid double counting.Comment: 7 pages, 7 figure

VCSEL intrinsic response extraction using T-Matrix formalism

We present a new method to remove the parasitics contribution to the VCSEL chip response, in order to obtain the intrinsic S21 behavior. The on-chip VCSEL is defined as two cascaded two-port subsystems representing the electrical access and the VCSEL optical cavity respectively. S11 and S21 parameters measurements are carried-out using a probe station to characterize the chip response. An electrical equivalent circuit defining the behavior of the electrical access is combined with T-Matrix formalism to remove the parasitics contribution from the measured S21 response. Results allow us to determine the intrinsic 3-dB bandwidth of the VCSEL