Atom interferometers measuring the fine structure constant and probing the dark sector

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)