  We propose a gedanken experiment on realizing thermofield double state (TFD)
by using analog black holes and provide an approach to test the scrambling
time. Through this approach, we demonstrate clearly how shock wave changes the
TFD state as time evolves. As the whole system evolves forward in time, the
perturbation of space-time geometry will increase exponentially. Finally, it
will destroy the entanglement between the two states of the thermal field, and
the mutual information between them is reduced to zero in the time scale of
scrambling. The results show that for perturbations of analogue black holes
embedded in AdS space, the scale of the scrambling time is closely related to
the logarithm of entropy of the black hole. The results provide further
theoretical argument for the scrambling time, which can be further falsified in
experiments.
