  The non-relativistic limit of integrable field theories at equilibrium has
been intensively studied in the previous years; the simplest non-trivial case
relates the sinh-Gordon model to the Lieb-Liniger model. Here we study this
non-relativistic limit out of equilibrium, namely in the time evolution after a
quantum quench. The obtained results agree with the known ones for the
Lieb-Liniger model, thus showing that the non-relativistic limit is applicable
in this out-of-equilibrium setting.
