Related papers: Coherent Smith-Purcell $\gamma$-Ray Emission
The direct and secondary nuclear excitation produced by an x-ray free electron laser when interacting with a solid-state nuclear target is investigated theoretically. When driven at the resonance energy, the x-ray free electron laser can…
The altered spontaneous emission of an emitter near an arbitrary body can be elucidated using an energy balance of the electromagnetic field. From a classical point of view it is trivial to show that the field scattered back from any body…
Employing the linear sigma model, the effective masses of quasi-particle excitations are found to exhibit significant variations within the phase diagram, which has a critical point at non-zero chemical potential, where a first-order phase…
The emission of light from a multiply excited atomic ensemble is examined and it is shown how symmetric (spin-wave) and non-symmetric states of excitation radiate into spatially separate field modes. This observation has potential…
We characterize the coherent dynamics of a two-level quantum emitter driven by a pair of symmetrically-detuned phase-locked pulses. The promise of dichromatic excitation is to spectrally isolate the excitation laser from the quantum…
When multiple quantum emitters radiate, their emission rate may be enhanced or suppressed due to collective interference in a process known as super- or subradiance. Such processes are well-known to occur also in light emission by free…
We discuss the possibility of observing ultra high energy cosmic ray sources inhigh energy gamma rays. Protons propagating away from their accelerators produce secondary electrons during interactions with cosmic microwave background…
The prompt emission of gamma-ray bursts (GRBs) is widely thought to be radiation from accelerated electrons, but an appreciably larger amount of energy could be carried by accelerated protons, particularly if GRBs are the sources of…
By measuring energy spectra of the electron emission from a sharp tungsten tip induced by few-cycle laser pulses, the laser-field dependence of the emission mechanism was investigated. In strong laser fields, we confirm the appearance of…
We investigate the transient coherent transmission of light through an optically thick cold stron-tium gas. We observe a coherent superflash just after an abrupt probe extinction, with peak intensity more than three times the incident one.…
It is well known that the vicinities of an atomic system may substantially affect its radiative properties. In this work, we consider the influence of a cosmic string background in the spontaneous emission of an excited atom. We start by…
We study the optical emission from single semiconductor quantum dots coupled to the optical modes of photonic crystal nanocavities. For dots that are both spectrally and spatially coupled, auto-correlation measurements reveal efficient…
We study $\gamma$-ray emission following $^{239}\mathrm{Pu}(n,\mathrm{f})$ over an incident neutron energy range of $2 < E_i < 40$ MeV. We present the first experimental evidence for positive correlations between the total angular momentum…
The flat decay phase in the first 1e2-1e4 seconds of the X-ray light curve of Gamma Ray Bursts (GRBs) has not yet found a convincing explanation. The fact that the optical and X-ray lightcurves are often different, with breaks at different…
Gamma-Ray Bursts (GRBs) are expected to efficiently accelerate protons up to relativistic energies. High-energy photons can originate from decay of neutral pions produced by the interaction of these protons with the medium surrounding the…
In this paper we present a fully selfconsistent SSC model with particle acceleration due to shock and stochastic acceleration (Fermi-I and Fermi-II-Processes respectively) to model the quiescent spectral energy distribution (SED) observed…
We report on the first observation of $\gamma$ rays emitted from an $sd$-shell hypernucleus, $\rm ^{19}_{\Lambda}F$. The energy spacing between the ground state doublet, $1/2^{+}$ and $3/2^{+}$ states, of $\rm ^{19}_{\Lambda}F$ is…
Systems of atoms coupled to a single or few waveguide modes provide a testbed for physically and practically interesting interference effects. We consider the dynamics of a pair of atoms, approximated as two-level quantum emitters, coupled…
Using Monte Carlo simulations, we demonstrate photopion production from Fermi-accelerated protons and the resulting neutrino production in gamma-ray bursts. Unless internal shocks occur at quite large distance from the center, ultra…
We have considered the possibility of using coherent Smith-Purcell radiation for the single-shot determination of the longitudinal profile of 50 fs (FWHM) long electron bunches. This length is typical for the bunches currently produced by…