2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/91048The conventional Wigner function is inappropriate in a quantum field theory setting because, as a quasiprobability density over phase space, it is not manifestly Lorentz covariant. A manifestly relativistic variant is constructed as a quasiprobability density over trajectories instead of over phase space.v3: as accepted by Phys. Lett. AQuantum PhysicsHigh Energy Physics - Theorytext