Atomic changes can map subterranean structures

Abstract

Atomic changes can map subterranean structuresA quantum device uses ultracold atoms to sense gravitational changes that can detect a tunnel under a city street. Here, scientists discuss the advance from the viewpoints of quantum sensing and geophysics. See p.590The paper in brief • Precise measurements of vertical gradients in gravity can be used to detect inhomogeneities in density under Earth's surface. • On page 590, Stray et al. 1 report a practical quantum sensor that uses atom interferometry to measure gravity gradients rapidly, and with high sensitivity.