Role of slow, out-of-equilibrium modes on the dynamic structure factor near the QCD critical point

Abstract

The role of slow out of equilibrium modes (OEM), introduced to extend the validity of hydrodynamics near the QCD critical point on the power spectrum of dynamical density fluctuations has been studied. We have used the equation of motion of slow modes for the situation when the extensive nature of thermodynamics is not altered due to the introduction of OEM. We find that the extensivity condition puts an extra constraint on the coupling of OEM with the four divergence of velocity. The dynamic structure factor (Snn) in presence of the OEM shows four Lorentzian peaks asymmetrically positioned about $\omega (\text{frequency})=0$, whereas the dynamic structure factor without the presence of any OEM shows three well-known Lorentzian peaks. The width of the peaks are reduced in presence of OEM. We find that the asymmetric peaks originate due to the coupling of the out-of-equilibrium modes with the hydrodynamic modes. It is also shown that the OEM has negligible effects on Snn if first order hydrodynamics (relativistic Navier-Stokes) is used. The introduction of OEM reduces the width of the Rayleigh peak indicating the reduction in the decay rate of the fluctuation which leads to slowing down, a well-known characteristics of the critical end point (CEP).

21 pages, 7 figures

References in corpus (9)

• Thermal Conductivity and Chiral Critical Point in Heavy Ion Collisions
• Hydrodynamic attractors in heavy ion collisions: a review
• Non-conformal attractor in boost-invariant plasmas
• On non-conformal kinetic theory and hydrodynamics for Bjorken flow
• Modeling the diffusive dynamics of critical fluctuations near the QCD critical point
• Baryon transport and the QCD critical point
• Net-baryon number variance and kurtosis within nonequilibrium chiral fluid dynamics
• Hydrodynamic Gradient Expansion Diverges beyond Bjorken Flow
• Dynamical spectral structure of density fluctuation near QCD critical point

Cited by in corpus (1)

• Correlation of density fluctuation in a magnetized QCD matter near the critical end point