  We theoretically propose an experimentally viable scheme to use an impurity
atom in a dipolar Bose-Einstein condensate (BEC), in order to probe analogue
low-energy Lorentz violation from the modified dispersion at high energies as
suggested by quantum theories of gravity. We show that the density fluctuations
in the dipolar BEC possess a Lorentz-violating Bogoliubov spectrum
$\omega_\mathbf{k}=c_0|\mathbf{k}|f(c_0|\mathbf{k}|/M_\star)$, with recovery of
approximate Lorentz invariance (LI) at energy scales much below $M_\star$. When
$f$ is adjusted to dip below unity somewhere, the impurity, analogously dipole
coupled to the density fluctuations, experiences analogue drastic Lorentz
violation at arbitrarily low energies, reproducing the same responds of
Unruh-DeWitt detector to Lorentz-violating quantum fields. Being a
fundamentally quantum mechanical device, our quantum fluid platform provides an
experimentally realizable test field to verify whether the effective low energy
theory can reveal unexpected imprints of the theory's high energy structure, in
quantum field theory.
