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ATLAS: Exploring Einstein’s Theories of Gravity Using the Quantum Nature of Atoms

ATLAS: Exploring Einstein’s Theories of Gravity Using the Quantum Nature of Atoms

Two major theories exist in modern physics: general relativity, the principle which governs our current understanding of gravity, and quantum mechanics, which explains the nature of extremely tiny objects such as electrons. Unfortunately, they are currently inconsistent with each other.

Certain modifications reconcile the two by allowing a violation of the so called universality of free fall, a cornerstone of Einstein’s general relativity. The universality of free fall states: that two bodies will drop at the same rate in a given gravitational field. We have recently performed an experiment looking for a violation of the universality of free fall using the quantum nature of potassium and rubidium atoms. By utilizing matter wave interference, it is possible to measure the magnitude of the gravitational acceleration. And so by, measuring the acceleration of two different atomic species, we were able to test the universality of free fall at a level of 10^-7. While substantially more precise experiments already exist, the test mass choice remains an important sensitivity lever when testing the universality of free fall. For the first time, we were able to perform such a measurement with two different neutral elements as test materials. The experiment opens the door to future tests of Einstein’s theory to be performed in large scale devices on ground, and even in space.

Our work has been published in Phys. Rev. Lett. 112, 203002 (2014) and covered in "Synopsis: Free Falling Matter Waves".

A PDF version of our publication can also be found here!