  We report on the experimental observation of scaling in the time evolution
following a sudden quench into the vicinity of a quantum critical point. The
experimental system, a two-component Bose gas with coherent exchange between
the constituents, allows for the necessary high level of control of parameters
as well as the access to time-resolved spatial correlation functions. The
theoretical analysis reveals that when quenching the system close to the
critical point, the energy introduced by the quench leads to a short-time
evolution exhibiting crossover reminiscent of the finite-temperature critical
properties in the system's universality class. Observing the time evolution
after a quench represents a paradigm shift in accessing and probing
experimentally universal properties close to a quantum critical point and
allows in a new way benchmarking of quantum many-body theory with experiments.
