Speaker
Description
First, We derive the analytic solutions for spin hydrodynamics with six spin degrees of freedom in Bjorken expansion and Gubser expansion. Analogous to the ordinary particle number density and chemical potential, we find that the spin density and spin chemical potential decay as ∼\tau^−1 and ∼\tau^(−1/3), respectively, where \tau is the proper time.
Second, we study the linear stability and thermal stability of the spin hydrodynamics with six spin degrees of freedom. We find that there exist some unstable and acausal modes in moving frames. To get rid of these unphysical modes, we need to modify the original spin hydrodynamics.
Third, we find that these unphysical modes disappear if the spin current is totally antisymmetric such that the spin density has only three degrees of freedom. By using the entropy principle, we derive the constitutive relations for spin hydrodynamics with three degrees of freedom. Taking the stability analysis for it, we find all modes can be causal and stable under certain conditions.
