Frankfurt Institute for Advanced Studies

About: Frankfurt Institute for Advanced Studies is a facility organization based out in Frankfurt am Main, Germany. It is known for research contribution in the topics: Baryon & Quark–gluon plasma. The organization has 798 authors who have published 2733 publications receiving 82799 citations. The organization is also known as: FIAS.

Direct Determination of the Magnetic Quadrupole Contribution to the Lyman-α 1 Transition in a Hydrogenlike Ion

Abstract: We report the observation of an interference between the electric dipole ($E1$) and the magnetic quadrupole ($M2$) amplitudes for the linear polarization of the Ly-${\ensuremath{\alpha}}_{1}$ ($2{p}_{3/2}\ensuremath{\rightarrow}1{s}_{1/2}$) radiation of hydrogenlike uranium. This multipole mixing arises from the coupling of the ion to different multipole components of the radiation field. Our observation indicates a significant depolarization of the Ly-${\ensuremath{\alpha}}_{1}$ radiation due to the $E1\mathrm{\text{\ensuremath{-}}}M2$ amplitude mixing. It proves that a combined measurement of the linear polarization and of the angular distribution enables a very precise determination of the ratio of the $E1$ and the $M2$ transition amplitudes and the corresponding transition rates without any assumptions concerning the population mechanism for the $2{p}_{3/2}$ state.

Biodamage via shock waves initiated by irradiation with ions.

Abstract: Radiation damage following the ionising radiation of tissue has different scenarios and mechanisms depending on the projectiles or radiation modality. We investigate the radiation damage effects due to shock waves produced by ions. We analyse the strength of the shock wave capable of directly producing DNA strand breaks and, depending on the ion's linear energy transfer, estimate the radius from the ion's path, within which DNA damage by the shock wave mechanism is dominant. At much smaller values of linear energy transfer, the shock waves turn out to be instrumental in propagating reactive species formed close to the ion's path to large distances, successfully competing with diffusion.

Sub-barrier fusion of neutron-rich nuclei and its astrophysical consequences

Abstract: Near-barrier fusion of neutron-rich nuclei was studied within the semiempirical channel coupling model for intermediate neutron rearrangement and within the time-dependent three-body Schr\"odinger equation The possibility of neutron transfer with positive $Q$ values considerably increases the barrier penetrability A huge enhancement of deep sub-barrier fusion probability was found for light neutron-rich weakly bound nuclei (such as $^{6}\mathrm{He}$) This may be quite important for astrophysical primordial and supernova nucleosynthesis

Synergies between Intrinsic and Synaptic Plasticity in Individual Model Neurons

Abstract: This paper explores the computational consequences of simultaneous intrinsic and synaptic plasticity in individual model neurons. It proposes a new intrinsic plasticity mechanism for a continuous activation model neuron based on low order moments of the neuron's firing rate distribution. The goal of the intrinsic plasticity mechanism is to enforce a sparse distribution of the neuron's activity level. In conjunction with Hebbian learning at the neuron's synapses, the neuron is shown to discover sparse directions in the input.

Λ Λ interaction from relativistic heavy-ion collisions

Abstract: The correlation between a pair of $\mathrm{\ensuremath{\Lambda}}$ hyperons emitted from a heavy-ion collision is shown to be sensitive to the $\mathrm{\ensuremath{\Lambda}}\phantom{\rule{0}{0ex}}\mathrm{\ensuremath{\Lambda}}$ interaction. The result bears on the existence of the $H$ dibaryon. A competing analysis by the STAR Collaboration appears in PRL 114, 022301 (2015).