Longitudinal dynamics from hydrodynamics with an order parameter  

作　　者：Shu Lin Gezheng Zhou 林树;周舸争(School of Physics and Astronomy,Sun Yat-Sen University,Zhuhai 519082,China)

机构地区：[1]School of Physics and Astronomy,Sun Yat-Sen University,Zhuhai 519082,China

出　　处：《Chinese Physics C》2021年第4期265-272,共8页中国物理C（英文版）

基　　金：in part Supported by NSFC(11675274,11735007)。

摘　　要：We studied coupled dynamics of hydrodynamic fields and order parameter in the presence of nontrivial longitudinal flow using the chiral fluid dynamics model.We found that longitudinal expansion provides an effective relaxation for the order parameter,which equilibrates in an oscillatory fashion.Similar oscillations are also visible in hydrodynamic degrees of freedom through coupled dynamics.The oscillations are reduced when dissipation is present.We also found that the quark density,which initially peaked at the boundary of the boost invariant region,evolves toward forward rapidity with the peak velocity correlated with the velocity of longitudinal expansion.The peak broadens during this evolution.The corresponding chemical potential rises due to simultaneous decrease of density and temperature.We compared the cases with and without dissipation for the order parameter and also the standard hydrodynamics without order parameter.We found that the corresponding effects on temperature and chemical potential can be understood from the conservation laws and different speeds of equilibration of the order parameter in the three cases.

关 键 词：relativistic hydrodynamics linear sigma model chiral phase transition heavy ion collisions EQUILIBRATION 

分 类 号：O35[理学—流体力学]