Atom interferometers have proven uniquely sensitive probes of effects at the interface of quantum mechanics and gravity. In order to move beyond technical limitations of standard atom interferometry, we have built the world's first atom interferometer in an optical cavity. Using a cavity provides power enhancement, wavefront filtering, and a precise beam geometry, enabling new techniques for manipulating matter waves.
We use this new atomic physics technology to address cosmological questions with laboratory precision. For example, we are exploring and testing the possibility that dark energy, which accounts for ~70% of the energy density of the universe, consists of a light scalar field. We have begun probing these fields in a search for chameleon dark energy. This is the first measurement of its kind. With feasible precision, we will be sensitive enough to discover or fully exclude several such theories.
In addition to studying dark sector physics, we will leverage the technical advantages of the cavity to enable new techniques such as large momentum transfer Bragg interferometry. These new tools will allow us to measure the gravitational analog of the Aharanov-Bohm effect.
Attractive force on atoms due to blackbody radiation. Philipp Haslinger, Matt Jaffe, Victoria Xu, Osip Schwartz, Matthias Sonnleitner, Monika Ritsch-Marte, Helmut Ritsch, and Holger Müller, arXiv:1704.03577.
Testing sub-gravitational forces on atoms from a miniature, in-vacuum source mass. Matt Jaffe, Philipp Haslinger, Victoria Xu, Paul Hamilton, Amol Upadhye, Benjamin Elder, Justin Khoury, and Holger Müller, Nature Physics (also, public link), and arxiv:1612.05171.