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.

Relativistic viscous hydrodynamics for heavy-ion collisions with ECHO-QGP

Abstract: We present ECHO-QGP, a numerical code for (3+1)-dimensional relativistic viscous hydrodynamics designed for the modeling of the space-time evolution of the matter created in high-energy nuclear collisions. The code has been built on top of the Eulerian Conservative High-Order astrophysical code for general relativistic magneto-hydrodynamics (Del Zanna et al. in Astron. Astrophys. 473:11, 2007] and here it has been upgraded to handle the physics of the Quark–Gluon Plasma. ECHO-QGP features second-order treatment of causal relativistic viscosity effects both in Minkowskian and in Bjorken coordinates; partial or complete chemical equilibrium of hadronic species before kinetic freeze-out; initial conditions based on the Glauber model, including a Monte-Carlo routine for event-by-event fluctuating initial conditions; a freeze-out procedure based on the Cooper–Frye prescription. The code is extensively validated against several test problems and results always appear accurate, as guaranteed by the combination of the conservative (shock-capturing) approach and the high-order methods employed. ECHO-QGP can be extended to include evolution of the electromagnetic fields coupled to the plasma.

Covariant version of Verlinde’s emergent gravity

Abstract: A generally covariant version of Erik Verlinde's emergent gravity model is proposed. The Lagrangian constructed here allows an improved interpretation of the underlying mechanism. It suggests that de Sitter space is filled with a vector field that couples to baryonic matter and, by dragging on it, creates an effect similar to dark matter. We solve the covariant equation of motion in the background of a Schwarzschild space-time and obtain correction terms to the noncovariant expression. Furthermore, we demonstrate that the vector field can also mimic dark energy.

NeuroXidence: reliable and efficient analysis of an excess or deficiency of joint-spike events

Abstract: We present a non-parametric and computationally efficient method named NeuroXidence that detects coordinated firing of two or more neurons and tests whether the observed level of coordinated firing is significantly different from that expected by chance. The method considers the full auto-structure of the data, including the changes in the rate responses and the history dependencies in the spiking activity. Also, the method accounts for trial-by-trial variability in the dataset, such as the variability of the rate responses and their latencies. NeuroXidence can be applied to short data windows lasting only tens of milliseconds, which enables the tracking of transient neuronal states correlated to information processing. We demonstrate, on both simulated data and single-unit activity recorded in cat visual cortex, that NeuroXidence discriminates reliably between significant and spurious events that occur by chance.

Possibilities for synthesis of new isotopes of superheavy elements in fusion reactions

Abstract: Background. In the ``cold'' fusion reactions based on the use of lead and bismuth targets, the proton-rich isotopes of superheavy (SH) elements up to $Z=113$ have been produced. More neutron-rich isotopes of SH elements (up to $Z=118$) have been synthesized in ``hotter'' fusion reactions of ${}^{48}$Ca with actinide targets. $\ensuremath{\alpha}$-decay half-lives of different isotopes of the same SH elements (for example, 112) were found to vary by several orders of magnitude. This indicates strong shell effects in this area of the nuclear map. The understanding of these effects and other properties of SH nuclei is strongly impeded by the absence of experimental data on decay properties of the not-yet-synthesized isotopes of SH elements located between those produced in the ``cold'' fusion reactions and those produced in the ``hot'' fusion reactions and also by the yet missing neutron-enriched isotopes of these elements.Purpose. In this paper we search for the optimal fusion reactions which may be used to fill this gap of the nuclear map and significantly extend the area of known SH nuclei.Method. For the calculation of the cross sections we use the same approach which was employed earlier for successful predictions of all ${}^{48}$Ca induced fusion reactions.Results. Several fusion reactions of the stable projectiles ${}^{40}$Ar, ${}^{44}$Ca, and ${}^{48}$Ca with different isotopes of actinides (lighter and heavier than those that have been already utilized in the Dubna experiments) could be used for synthesis of new SH nuclei. Predicted cross sections for the production of new isotopes of SH nuclei were found to be quite large, and the corresponding experiments can be easily performed at existing facilities. For the first time a ``narrow pathway'' to the middle of the island of stability was found owing to possible ${\ensuremath{\beta}}^{+}$ decay of SH nuclei ${}^{291}$115 and ${}^{291}$114 which could be formed in ordinary fusion reactions.