Relativistic second-order spin hydrodynamics: A Kubo-type formulation for the quark-gluon plasma

Abstract: Building upon Zubarev's nonequilibrium statistical operator formalism, we derive a relativistic canonical-like second-order spin hydrodynamics for two power-counting schemes. We obtain comprehensive second-order expressions for dissipative fluxes, including the shear stress tensor, bulk viscous pressure, charge-diffusion currents, rotational stress tensor, boost heat vector, and spin tensor-related dissipative flux. By introducing novel transport coefficients and expressing them in terms of equilibrium correlation functions, we establish new Kubo-type formulas for second-order transport. Our findings have significant implications for understanding the collective spin dynamics of strongly interacting matter and provide a robust theoretical basis for future experimental and theoretical studies.