Tame the Umklapp Processes in Real-Time Lattice Simulation for Hydrodynamics: An Ising Field Theory Study (opens in new tab)

We calculate the real-time symmetric correlation function of the stress-energy tensor for a non-integrable Ising field theory consisting of three stable scalar particles via lattice Hamiltonian simulation. Using classical exact diagonalization and the matrix product state tensor network methods, we find that in the scaling region of the lattice theory, Umklapp processes are suppressed and the sound modes of relativistic hydrodynamics emerge at...