Macroscopic quantum experiments
By studying the quantum-mechanical behaviour of ever larger and more massive objects,
researchers stand a better chance of building reliable quantum computers or developing other
applications of quantum information science. The current world record for the most massive
objects to exhibit quantum interference in a two-slit type experiment, i.e. to demonstrate
wave-like behaviour despite their corpuscular character, are fluorinated fullerene molecules
C60F48 with a mass of 1632 atomic mass units (top left) (Phys. Rev. Lett. 91 090408). The
largest object showing interference is the molecule “azobenzene” (bottom) (Nature Physics 3
711), as demonstrated by Markus Arndt’s team at the University of Vienna. Mechanical
resonators (top right) have not yet entered the quantum regime, but this could soon change
with such objects being cooled to their quantum ground state. This particular resonator
contains a highly reflecting mirror placed on top of a vibrating singly clamped cantilever, which
can be actuated via radiation pressure in combination with a high-finesse optical cavity.