  In this paper we will study for the first time how the wave-packet of a
self-gravitating meso-scopic system spreads in theories beyond Einstein's
general relativity. In particular, we will consider a ghost-free infinite
derivative gravity, which resolves the $1/r$ singularity in the potential -
such that the gradient of the potential vanishes within the scale of
non-locality. We will show that a quantum wave-packet spreads faster for a
ghost-free and singularity-free gravity as compared to the Newtonian case,
therefore providing us a unique scenario for testing classical and quantum
properties of short-distance gravity in a laboratory in the near future.

General Relativity and Quantum Cosmology;Quantum Physics