Quantum Force Measurements Using Macroscopic Molecular Tunneling

Microscopic force sensing is at the center of many technologies, such as atomic force microscope, inertial sensor and pressure sensor. While the stress or Van der Waals force are measured by these sensors, Casimir force is in the same scope but seldom probed experimentally. Casimir force arises from the alteration of boundary in zero point electromagnetic field, as predicted by quantum field theory. In condensed matter, alternation of the electronic wave function on a metallic surface also causes forces between nano structures under the same principle. We present a technique to measure this electron-mediated force between atomic objects using scanning tunneling microscope. Unlike Van der Waals force, this force is a strong function of geometry. The force is measured under different geometrical designs. The results are consistent with theoretical calculations.