2024/10/05 by Dey, Sourav, Das, Arpan
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th) #Nuclear Theory (nucl-th)
paper · doi:10.48550/arxiv.2410.04141
We present a first-order dissipative spin hydrodynamic framework, where the spin chemical potential ωμν is treated as the leading term in the hydrodynamic gradient expansion, i.e., ωμν∼ O(1). We argue that for the consistency of the theoretical framework, the energy-momentum tensor needs to be symmetric at least up to order O(∂). We consider the phenomenological form of the spin tensor, where it is anti-symmetric in the last two indices only. A comprehensive analysis of spin hydrodynamics is conducted using both macroscopic entropy current analysis and microscopic Kubo formalism, establishing consistency between the two approaches. A key finding is the entropy production resulting from spin-orbit coupling, which alters the traditional equivalence between the Landau and Eckart fluid frames. Additionally, we identify cross-diffusion effects, where vector dissipative currents are influenced by gradients of both spin chemical potential and chemical potential corresponding to the conserved charge through off-diagonal transport coefficients. Two distinct methods for decomposing the spin tensor are proposed, and their equivalence is demonstrated through Kubo relations.