2GeV. For one type of coupling this is eleven orders of magnitude more stringent than constraints obtained from cosmological and solar system tests, and excludes previously popular models that require the coupling scale to lie close to the dark energy scale, Λ ~ 10-3eV. These existing searches are not optimised to search for dark energy, as the dark energy particle is significantly lighter than other new physics particles, and its couplings to matter can depend on the energy and momentum in the collision. Constraints could easily be improved with a targeted search. The key advantage of laboratory searches over cosmological surveys is that if dark energy is detected in the laboratory we are able to study this new substance actively, rather than only passively through astronomical observations, leading to rapid further advances in understanding. However, this does not negate the need to ensure that cosmological observations take full account of the possible range of behaviours for dark energy. Only a combination of terrestrial and cosmological data can give us a comprehensive picture of dark energy, how it interacts with standard model particles, and how it behaves on all scales in the universe.
