2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/187939Combining a lattice path integral formulation for thermodynamics with the solution of the quantum inverse scattering problem for local spin operators, we derive a multiple integral representation for the time-dependent longitudinal correlation function of the spin-1/2 Heisenberg XXZ chain at finite temperature and in an external magnetic field. Our formula reproduces the previous results in the following three limits: the static, the zero-temperature and the XY limits.22 pages, v4: typos corrected, published versionStatistical MechanicsHigh Energy Physics - TheoryMathematical PhysicsQuantum AlgebraExactly Solvable and Integrable Systemstext