Prague, 28 June 2017
- Published on Wednesday, 14 June 2017 16:12
In high-temperature field theory applied to nuclear physics, in particular to relativistic heavy-ion collisions, it is a longstanding question how hadrons precisely transform into a quark-gluon matter and back. The change in the effective number of degrees of freedom is rather gradual than sudden, despite the identification of a single deconfinement temperature. In order to gain an insight into this issue while considering the structure of the QGP we review the spectral function approach and its main consequences for the medium properties, including the shear viscosity. The figure plots a sample spectral density on the left and the effective number of degrees of freedom (energy density relative to the free Boltzmann gas) to the right. Two thin spectral lines result in a doubled Stefan-Boltzmann limit (SB), while any finite width reduces the result down to a single SB. When spectral lines become wide, their individual contributions to energy density and pressure drops. Continuum parts have negligible contribution. This causes the melting of hadrons like butter melts in the Sun, with no latent heat in this process.
- Published on Wednesday, 14 June 2017 14:36
In the general framework of transient coupled calculations, new developments of an accurate neutron kinetics model able to characterize spatial decoupling are described, together with an application to sodium fast reactors.
- Published on Tuesday, 13 June 2017 10:03
The publishers of The European Physical Journal C – Particles and Fields are pleased to announce the appointment of Professor Dieter Zeppenfeld as new Editor-in-Chief for Theoretical Physics I: Phenomenology of the Standard Model and Beyond, replacing Professor Gino Isidori. Dieter Zeppenfeld is Head of the Institute for Theoretical Physics at the Karlsruher Institut für Technologie (KIT) and leads a research group on Collider Physics at KIT.