Related papers: Proposal for a Nuclear Gamma-Ray Laser of Optical …
Merger and accretion shocks in clusters of galaxies can accelerate particles via first order Fermi process. Since this mechanism is believed to be intrinsically efficient, shocks are expected to be modified by the backreaction of the…
The effects of neutron irradiation on materials are often interpreted in terms of atomic recoils, initiated by neutron impacts and producing crystal lattice defects. In addition, there is a remarkable two-step process, strongly pronounced…
We report on the amplification of an optical vortex beam carrying orbital angular momentum via induced narrow Raman gain in an ensemble of cold cesium atoms. A 20\% single-pass Raman gain of a weak vortex signal field is observed with a…
Laser excitation of thorium-229 nuclei in doped wide bandgap crystals has been demonstrated recently, opening the possibility of developing ultrastable solid-state clocks and sensitive searches for new physics. We develop a quantitative…
Our analysis of the experimental data related to nonphotochemical laser induced nucleation in solutions leads to the inevitable conclusion that the phase transformation is initiated by particles that are metallic in nature. This conclusion…
We consider the nuclear absorption of dark matter as an alternative to the typical indirect detection search channels of dark matter decay or annihilation. In this scenario, an atomic nucleus transitions to an excited state by absorbing a…
The low-lying isomeric state of $^{229}$Th provides unique opportunities for high-resolution laser spectroscopy of the atomic nucleus. We determine the energy of this isomeric state by taking the absolute energy difference between the…
We show that plasmons in two-dimensional graphene can have net gain at terahertz frequencies. The coupling of the plasmons to interband electron-hole transitions in population inverted graphene layers can lead to plasmon amplification…
Excitation of the anomalously low lying nuclear isomer $^{229m}$Th$(3/2^+, 8.28 \pm 0.17$ eV) in the process of inelastic electron scattering is studied theoretically in the framework of the perturbation theory for the quantum…
In this contribution we will discuss recent results concerning the intensity and the angular distribution of the gamma-ray and neutrino emissions as should be originated from the hadronic scattering of cosmic rays (CR) with the interstellar…
The harmonic emission from cluster nanoplasmas subject to short, intense infrared laser pulses is analyzed by means of particle-in-cell simulations. A pronounced resonant enhancement of the low-order harmonic yields is found when the Mie…
$\gamma$-ray production cross sections have been measured in proton irradiations of N, Ne and Si and $\alpha$-particle irradiations of N and Ne. In the same experiment we extracted also line shapes for strong $\gamma$-ray lines of $^{16}$O…
Optical parametric amplification/oscillation provide a powerful tool for coherent light generation in spectral regions inaccessible to lasers. Parametric gain is based on a frequency {\it down-conversion} process, and thus it can not be…
A new parameter regime of laser wakefield acceleration driven by sub-petawatt femotsecond lasers is proposed, which enables the generation of relativistic electron mirrors further accelerated by the plasma wave. Integrated particle-in-cell…
Particle acceleration in clusters of galaxies is expected to take place at both merger and accretion shocks. The electron component may be energized to energies of several TeV, and upscatter a small fraction of the photons in the cosmic…
The possibility of $\gamma-$ray laser generation by the radiation of wiggling electrons in an usual background laser is discussed.
We investigate theoretically the possibility of achieving the stimulated amplification of $\gamma$-rays. Herein, our approach circumvents the so-called ``graser dilemma" through a non-linear, multi-photon mechanism. Our work foresees the…
It is crucial to identify the ultrahigh-energy cosmic-ray (UHECR) sources and probe their unknown properties. Recent results from the Pierre Auger Observatory favor a heavy nuclear composition for the UHECRs. Under the requirement that…
Inelastic dark matter and strongly interacting dark matter are poorly constrained by direct detection experiments since they both require the scattering event to deliver energy from the nucleus into the dark matter in order to have…
Since it is possible to form laser pulses with a frequency much larger than the frequency of visible light, Prof. T.Tajima proposed using such pulse to accelerate the particles at its injection into the crystal. Here, the wakefield…