This paper shows the coordinates influence on singularity of a three degree-of-freedom structure, namely, three-Universal-Prismatic-Spherical (3-UPS) parallel manipulator. Rotational coordinates, which are chosen to define the orientation of the platform, affect the singularity of the manipulator. Euler parameters, which don't have any inherent geometrical singularity are utilized, however they...

It is now well established' that the nonlocality of the first order Kerman-McManus-Thaler (KMT) optical potential for nucleon-nucleus scattering must be treated accurately in order to reproduce experimental data for proton-nucleus elastic scattering at intermediate energies. It thus proves very convenient to perform the associated numerical calculations in momentum space. It has been shown clea...

The effective coupling of QCD is measured by using the gauge configurations produced by the MILC collaboration in which the Kogut Susskind (KS) fermion is incorporated and by using that produced by the QCDOC collaboration in which the domain wall fermion (DWF) is incorporated. We fix the gauge to the Landau gauge and to the Coulomb gauge. The infrared effective coupling in the Coulomb gauge agr...

We present an efficient and accurate grid method for solving the time-dependent Schrodinger equation for an atomic system interacting with an intense laser pulse. Instead of the usual finite difference (FD) method, the radial coordinate is discretized using the discrete variable representation (DVR) constructed from Coulomb wave functions. For an accurate description of the ionization dynamics ...

We calculate the spin-drag transresistivity ρ↑↓(T ) in a two-dimensional electron gas at temperature T in the random phase approximation. In the lowtemperature regime we show that, at variance with the three-dimensional low-temperature result [ρ↑↓(T ) ∼ T 2], the spin transresistivity of a twodimensional spin unpolarized electron gas has the form ρ↑↓(T ) ∼ T 2 lnT . In the spin-polarized case t...

Singularity of the potential function makes quantum tunneling problem mathematically underdetermined. To circumvent difficulties it introduced in physics, a singularity cutoff is often used, followed by reverse limit transition, or suitable self-adjoint extension Hamiltonian along entire coordinate axis made. However, both them somehow affect singular nature problem, and so I discuss here how w...

We consider the long-time behavior of solutions to massless Dirac equation coupled a Coulomb potential. For nice enough initial data, we find joint asymptotic expansion for near null and future infinities characterize explicitly decay rates seen in expansion. This paper can be viewed as successor previous work on expansions radiation field [BVW15], [BVW18], [BM19]. The key new elements are prop...

We calculate the exciton binding energy in narrow band gap single-walled carbon nanotubes with and graphene nanoribbons, accounting for the quasi-relativistic dispersion of electrons and holes. Exact analytical solutions of the quantum relativistic two-body problem are obtained for several limiting cases. We show that the binding energy scales with the band gap, and conclude on the basis of the...

This paper analyzes how special relativity changes the equation for many-body-induced current density starting from Foldy–Wouthuysen diagonalization of Dirac–Coulomb Hamiltonian. differs that obtained with Gordon decomposition due to presence a spin-orbit coupling contribution not considered before many-body molecular systems. diverges on atomic nuclei nature point charges in nonrelativistic ap...