Open Access

Nora Weickgenannt

• The aim of this thesis is to provide a complete and consistent derivation of second-order dissipative relativistic spin hydrodynamics from quantum field theory. We will proceed in two main steps. The first one is the formulation of spin kinetic theory from quantum field theory using the Wigner-function formalism and performing an expansion in powers of the Planck constant. The essential ingredient here is the nonlocal collision term. We will find that the nonlocality of the collision term arises at first order in the Planck constant and is responsible for the spin alignment with vorticity, as it allows for conversion between spin and orbital angular momentum. In the second step, this kinetic theory is used as the starting point to derive hydrodynamics including spin degrees of freedom. The so-called canonical form of the conserved currents follows from Noether’s theorem. Applying an HW pseudo-gauge transformation, we obtain a spin tensor and energy-momentum tensor with obvious physical interpretation. Promoting all components of the HW tensors to be dynamical, we derive second-order dissipative spin hydrodynamics. The additional equations of motion for the dissipative currents are obtained from kinetic theory generalizing the method of moments to include spin degrees of freedom.