ELFT HÍRADÓ

[somogyi <somogyi.gabor AT wigner.hu>]

Wigner FK RMI Elméleti Osztály Szemináriuma
Tisztelettel meghívjuk


                  David Wagner
                  (Goethe-Universität Frankfurt am Main)


"Inverse-Reynolds Dominance approach to transient fluid dynamics"


     illetve


                  Victor E. Ambruș
                  (Universitatea de Vest Din Timisoara)


"Applicability of hydrodynamics in relativistic heavy-ion collisions"


     címmel tartandó szemináriumára.


Kivonatok:



Inverse-Reynolds Dominance approach to transient fluid dynamics: We 
consider the evolution equations for the bulk viscous pressure, 
diffusion current and shear tensor derived within the second order 
relativistic dissipative hydrodynamics from kinetic theory. By matching 
the irreducible moments of the single-particle distribution function to 
the dissipative quantities, we obtain relaxation-type equations 
featuring a number of transport coefficients, which can be calculated to 
arbitrary precision. In the case of hard-sphere interactions, the values 
of these transport coefficients are compatible with the second law of 
thermodynamics.


Applicability of hydrodynamics in relativistic heavy-ion collisions: 
This talk focuses on the comparison between the predictions of 
relativistic hydrodynamics and kinetic theory for flow observables in 
the context of heavy-ion collisions. While the two theories agree for 
systems which are close to equilibrium (after hydrodynamization), their 
far-from-equilibrium behaviours differ considerably (during 
preequilibrium). An analysis of the early-time Bjorken flow attractor in 
the two theories reveals that discrepancies during the (short) 
preequilibrium evolution leads to significant discrepancies in flow 
observables. As a workaround, we propose a rescaling of the initial 
conditions for hydrodynamics that compensate for the differences in the 
early-stage dynamics, which brings (ideal and viscous) hydrodynamics in 
agreement with kinetic theory provided that the equilibration time scale 
is shorter than the time scale associated to transverse expansion 
(typically the system size, R).



Helye: Wigner FK RMI III. ép. Tanácsterem
Ideje: 2023 április 3 hétfő d.e. 11 óra (SZOKÁSOSTÓL ELTÉRŐ NAP ÉS 
IDŐPONT)
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Szívesen látunk minden érdeklődőt.


                             Somogyi Gábor