We argue that due to various restrictions only necklaces and monopolonia survive as potential sources of ultra-high energy cosmic rays, among the topological defects studied so far. Other promising sources which are similar to topological defects are relic superheavy particles. All these sources have an excess of pions (and thus photons) over nucleons at production. We demonstrate that in the c...

Yuichi Hoshino Kushiro National College of Technology, Otanoshike nishi 2-32-1,Kushiro, Hokkaido 084,Japan Abstract We evaluate the spectral function of scalar and spinor propagator in three dimensional quantum electrodynamics with the use of Ward-Identity for soft-photon emission vertex.We work well in position space to treat infrared divergences in our model. Exponentiation of one-photon matr...

We study the photon generation in a transmission line oscillator coupled to a driven qubit in the presence of a dissipative electromagnetic environment. It has been demonstrated previously that a population inversion in the qubit can lead to a lasing state of the oscillator. Here we show that the circuit can also exhibit the effect of "lasing without inversion." It arises since the coupling to ...

The energy transfer mechanism between luminescent centers (LCs) and Er3+ in erbium-doped silicon-rich oxide (SROEr) films prepared by electron beam evaporation is investigated. Intense photoluminescence of the LCs (weak oxygen bonds, neutral oxygen vacancies, and Si=O states) within the active matrixes is obtained. Fast energy transfer from Si=O states to Er3+ takes advantage in the SROEr film ...

Semiconductor superlattice micro-/nanowires could greatly increase the versatility and power of modulating electronic (or excitonic, photonic) transport, optical properties. In this communication, we report growth of a semiconductor CdS/CdS:SnS(2) superlattice microwire through a coevaporation technique with microenvironmental control. Such a novel superlattice microwire can modulate the excito...

The High-Brightness Electron Source Lab (HBESL) at Fermilab operates an L-band RF gun (1.3-GHz) that incorporates a Cesium Telluride (Cs2Te) photocathode illuminated by an ultra-short (sub-100 fs) laser pulses. In this contribution we report recent studies on exploring the electron beam emission using 800 nm laser pulses (instead of the 266 nm nominal wavelength used for linear photoemission). ...