Background: This postdoctoral researcher will join the newly established group of Inamori FP Associate Professor Joshua Foo at the Institute for Advanced Study, Kyushu University. The research will focus on developing experimental proposals to probe the interplay of quantum mechanics and spacetime physics in low-energy systems such as atomic clocks, mechanical resonators, and photonic interferometers. Relevant directions for exploration include quantum extensions of relativistic principles, foundations of relativistic quantum mechanics, and tabletop tests of weak field quantum gravity.