Holger Müller, Assistant Professor of Physics, UC Berkeley
With new technologies, atom interferometers have become instruments for measurements accross physics at 10^-10 sensitivity [1]. For example, we are now close to reporting a new measurement of the fine structure constant alpha with an anticipated accuracy of 2.5x10^-10, allowing for ultra-precise tests of the standard model.
Chameleons are flexible models for dark energy. They become unmeasurably short-ranged in the presence of bulk matter but can now be probed in our cavity-based atom interferometer [2]. We rule out chameleons and a range of other dark energy candidates that would reproduce the observed cosmic acceleration [3]. With upgrades, we may sense any chameleons and a wide class of other exotic models for dark energy and dark matter, such as B-L bosons or f(R) gravity.
[1] Phys. Rev. Lett. 115, 083002 (2015)
[2] Phys. Rev. Lett. 114, 100405 (2015)
[3] Science 349, 849 (2015)