Related papers: Proposal for a Nuclear Gamma-Ray Laser of Optical …
Classical novae are cataclysmic binary star systems in which the matter of a companion star is accreted on a white dwarf (WD). Accumulation of hydrogen in a layer eventually causes a thermonuclear explosion on the surface of the WD,…
A general quantum mechanical theory is developed for the isomeric excitation of $^{229}$Th in strong femtosecond laser pulses. The theory describes the tripartite interaction between the nucleus, the atomic electrons, and the laser field.…
The S-matrix element and the cross section of the laser-assisted nuclear photoeffect are recalculated in a gauge invariant manner taking into account the effect of the Coulomb field of the remainder nucleus. The \gamma-photon energy…
We explore the ability of two-dimensional periodic atom arrays to produce light amplification and generate laser emission when gain is introduced through external optical pumping. Specifically, we predict that lasing can take place for…
Significant improvements in our understanding of nuclear $\gamma$-ray line production and instrument performance allow us to better characterize the continuum emission from electrons at energies $\gtrsim$ 300 keV during solar flares. We…
Conditions for the appearance of a nuclear exciton in a crystal consisting of excited and unexcited nuclei of a given type are determined. The total probabilities for spontaneous -emission by a single excited nucleus or by an arbitrary…
From fusion dynamics in stars, to terrestrial lightning events, to new prospects of energy production or novel light sources, hot dense plasmas are of importance for an array of physical phenomena. Due to a plethora of correlations in…
We propose a simple approach to measure the energy of the few-eV isomeric state in Th-229. To this end, U-229 nuclei are doped into VUV-transparent crystals, where they undergo alpha decay into Th-229, and, with a probability of 2%,…
A long laser beam propagating through an underdense plasma produces a positively charged ion channel by expelling plasma electrons in the transverse direction. We consider the dynamics of a test electron in a resulting two-dimensional…
The Na59 collaboration aims to measure the linear polarization of its photon beam in the 20-170 GeV range, using an aligned thin crystal. The tracks of $e^-/e^+$ pairs created in two different crystal targets, germanium and diamond, are…
$^{229}$Th is the only known nucleus with an excited state that offers the possibility for a direct laser excitation using existing laser technology. Its excitation energy has been measured indirectly to be 7.8(5) eV ($\approx$160 nm). The…
The phenomenon of polarization of nuclei in the process of stimulated recombination of atoms in the field of circularly polarized laser radiation is considered. This effect is considered for the case of the proton-electron beams used in the…
In high neutron flux environments where isomers can be strongly populated by nucleonic reactions, isotope abundances from reaction network chains can be affected by the population of nuclear isomers. At high temperatures and densities there…
We study the possibility to influence the lifetime of nuclear isomeric states with the aid of incident fluxes of photons. We assume that a nucleus initially in an isomeric state |i> first absorbs an incident photon of energy E_{ni} to reach…
A new scheme for amplification of coherent gamma rays is proposed. The key elements are crystalline undulators - single crystals with periodically bent crystallographic planes exposed to a high energy beam of charged particles undergoing…
Using the Brink-Axel hypothesis we derive the rate $R$ for nuclear dipole excitation by a laser pulse carrying $N \gg 1$ photons with average energy $\hbar \omega_0 \approx 5$ MeV. As expected $R \propto (\hbar \omega_0)^3$. The rate is…
A substantial increase of the mean logarithmic mass $<\ln A>$ of galactic cosmic rays {\em vs} energy has been observed . We study three effects that could explain this trend i) different source spectra for protons and heavy nuclei ii) a…
We use above-bandgap optical excitation, via a 1047 nm laser, to hyperpolarize the $^{31}$P spins in low-doped (N$_D =6\times10^{15}$ cm$^{-3}$) natural abundance silicon at 4.2 K and 6.7 T, and inductively detect the resulting NMR signal.…
Bulk 13C polarization can be strongly enhanced in diamond at room-temperature based on the optical pumping of nitrogen-vacancy color centers. This effect was confirmed by irradiating suitably aligned single-crystals at a ~50 mT field…
Active energy compression scheme is presently being investigated for future laser-plasma accelerators. This method enables generating laser-plasma accelerator electron beams with a small, $\sim 10^{-5}$, relative slice energy spread. When…