Probing Klein tunnelling through quantum quenches.

We study the interplay between an inhomogeneous quantum quench of the external potential in a system of relativistic fermions in one-dimension and the well-known Klein tunneling. We find that the large time evolution is characterized by particle production at a constant rate which we derive analytically. The produced particles can be physically interpreted according to a semiclassical picture and the state reached in the long time limit can be classified as a non-equilibrium-steady-state. Such a quantum quench can be used in order to observe macroscopic effects of Klein tunneling in transport, with potential implementations with current experimental setups. [ABSTRACT FROM AUTHOR]