58 research outputs found
Finite Mass Effect on Two Photon Processes in Hydrogenic Systems: Effective Scalar Photon Interaction
We consider a hydrogenic system with a nucleus of finite mass. The coupling
of the radiation field to the center of mass motion gives rise to an effective
scalar type coupling. This induced scalar photon interaction emerges as a
correction in competition with the usual multipole interactions. This effect is
particularly important in positronium where the electric quadrupole interaction
is totally suppressed. We illustrate this effect with the two-photon decay of
metastable hydrogenic systems.Comment: 12 pages, Latex, no figure. Version to appear in Phys. Lett.
Perturbative Scattering Phase Shifts in One-Dimension: Closed-form Results
A simple closed form expression is obtained for the scattering phase shift
perturbatively to any given order in effective one-dimensional problems. The
result is a hierarchical scheme, expressible in quadratures, requiring only
knowledge of the zeroth order solution and the perturbation potential.Comment: 10 pages in REVTe
Supersymmetric solutions of PT-/non-PT-symmetric and non-Hermitian Screened Coulomb potential via Hamiltonian hierarchy inspired variational method
The supersymmetric solutions of PT-symmetric and Hermitian/non-Hermitian
forms of quantum systems are obtained by solving the Schrodinger equation for
the Exponential-Cosine Screened Coulomb potential. The Hamiltonian hierarchy
inspired variational method is used to obtain the approximate energy
eigenvalues and corresponding wave functions.Comment: 13 page
van der Waals coefficients for positronium-atom interactions
The van der Waals coefficients for positronium interactions with a number of rare gases (He, Ne, Ar, Kr, and Xe) and alkali-metal atoms (Li, Na, K, and Rb) are estimated using a variety of ab initio and semiempirical methods. Dispersion coefficients are also presented for atomic hydrogen and a number of rare-gas and alkali-metal atoms for validation purposes
Polarization correlation in the two-photon decay of atomic hydrogen: nonlocality versus entanglement
Effects of retardation on electromagnetic self-energy of atomic states
The significance of retardation effects in photon emissions and absorption is emphasized in the calculation of self-energy. It is explicitly demonstrated that inclusion of such effects leads to a finite answer for the shifts of atomic energy levels in a nonrelativistic theory without cutoff. Ambiguities that exist in the mass renormalization in the non-relativistic approach are pointed out. Such ambiguities vanish from the relativistic theory. Explicit calculation is carried out in the case of hydrogen by utilizing the Coulomb Green's function. The advantage of the present approach in calculating self-energy shift in high Z hydrogenic ions is suggested. (auth
Mechanical properties of fabric materials for draping simulation
Most of the cloth simulation and modelling techniques rely on the energy function of the system. The geometric deformation is related to the energy function by the fabric material characteristics, which are usually difficult to measure directly. This paper discusses how the fabric material properties are related to the measurable mechanical properties of the fabric such as tensile modulus, Poisson's ratio etc. These properties are incorporated into a cloth simulator to produce draping results. The simulated image and real object are then compared to show the realism
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