Related papers: Calculation of Positron Channeling Radiation with …
The goal of this paper is to calculate bound, resonant and scattering states in the coupled-channel formalism without relying on the boundary conditions at large distances. The coupled-channel solution is expanded in eigenchannel bases i.e.…
In this work we define single-particle potentials for a positron and a positronium atom interacting with light atoms (H, He, Li and Be) by inverting a single-particle Schr\"odinger equation. For this purpose, we use accurate energies and…
A polar-coded modulation scheme for deep-space optical communication is proposed. The photon counting Poisson channel with pulse position modulation (PPM) is considered. We use the fact that PPM is particularly well suited to be used with…
The shift of atomic energy levels due to hadronic vacuum polarization is evaluated in a semiempirical way for hydrogenlike ions and for muonic hydrogen. A parametric hadronic polarization function obtained from experimental cross sections…
Energetic positrons produced in annihilation or decay of dark matter particles in the Milky Way can serve as an important indirect signature of dark matter. Computing the positron flux expected in a given dark matter model involves solving…
Recent results in the theory of multiphoton spectra for coherent radiation sources are overviewed, with the emphasis on channeling radiation. For the latter case, the importance of the order of resummation and averaging is illustrated.…
We develop a method to compute the vacuum polarization energy for coupled scalar fields with different masses scattering off a background potential in one space dimension. As an example we consider the vacuum polarization energy of a…
Accretion onto compact objects plays a central role in high energy astrophysics. In these environments, both general relativistic and plasma effects may have significant impacts upon the spectral and polarimetric properties of the accretion…
The supersolid phase of a dipolar Bose-Einstein condensate has an intriguing excitation spectrum displaying a band structure. Here, the dressing of an impurity in a one-dimensional dipolar supersolid with the excitations of the supersolid…
Birefringent crystals are extensively used to manipulate polarized light. The generalized transfer matrix developed allows efficient calculation of the full polarization state of light transmitted through and reflected by a stack of…
Through the use of perturbation theory, in this work we develop a method which allows for a substantial reduction in the size of the plane-wave basis used in density-functional calculations. This method may be used for both pseudopotentials…
The coupled-channel technique augments a non-relativistic distorted wave born approximation scattering calculation to include a coupling to virtual states from the negative energy region. It has been found to be important in low energy…
Particles scattered off the nuclear target acquire a polarization if the nuclei have a non zero analyzing power. This effect is enhanced when particles traverse a bent crystal. Such enhancement under certain assumptions allows one to…
We study the modifications of synchrotron radiation of charges in a storage ring as they are cooled. The pair correlation lengths between the charges are manifest in the synchrotron radiation and coherence effects exist for wavelengths…
We study the polarization of an electron scattered by different static potentials. The initial state of the electron is chosen as a wavepacket to construct the definite orbital angular momentum, and the final polarization of the electron,…
Basic properties of radiation of the atomic chains excited by a channeling particle are considered. Using a very simple two-dimensional model of a crystal lattice we have shown that the main part of this radiation is generated on the…
We demonstrate an isotropic depolarizing channel with a controllable degree of depolarization. The depolarizer is composed of four birefringent crystals and half-wave plates. Quantum process tomography results of the depolarization effect…
Using the complex Kohn method, we have calculated variational values of phase shifts and the annihilation parameter, Z_{eff}, for the elastic scattering of positrons by molecular hydrogen. Our results are sensitive to small changes in the…
The process of electroproduction of the electron-positron pair by high energy electron in an oriented single crystal is investigated. Two contributions are considered: the direct (one-step) process via the virtual intermediate photon and…
The problem of optical radiation produced by a bunch of relativistic positrons channeled to a crystalline undulator (CU) is considered. Taking into account the polarization of the crystal medium, an energy threshold takes place to form the…