Gravity, blackbody radiation and chameleons – Towards lattice atom interferometry
by Dr. Philipp Haslinger (Berkeley, Department of Physics, University of California)
at SMI - Boltzmanngasse 3, 1090 Wien ( 3-2-08 - Seminarraum )
Dr. Philipp Haslinger
Berkeley, University of California
Within the last decades atom interferometry has proven its surprising versatility to sense with high precision tiniest forces. In this talk I will give an overview of our recent work using an optical cavity enhanced atom interferometer to sense with gravitational strength for fifths forces1,2 and for an on the first-place counterintuitive inertial property of blackbody radiation3. I will conclude with perspectives on the next generations of optically levitated atom interferometric sensors.
If dark energy, which drives the accelerated expansion of the universe, consists of a light scalar field it might be detectable as a “fifth force” between normal-matter objects. In order to be consistent with cosmological observations and laboratory experiments, some leading theories use a screening mechanism to suppress this interaction. However, atom-interferometry presents a tool to reduce this screening4 on so-called chameleon models5. By sensing the gravitational acceleration of a 0.19 kg in vacuum source mass which is 10-9 times weaker than Earth´s gravity, we reached a natural bound for cosmological motivated scalar field theories and were able to place tight constraints1,2.
Blackbody (thermal) radiation is emitted by objects at finite temperature with an outward energy-momentum flow, which exerts an outward radiation pressure. At room temperature e.g. a cesium atom scatters on average less than one of these blackbody radiation photons every 108 years. Thus, it is generally assumed that any scattering force exerted on atoms by such radiation is negligible. However, particles also interact coherently with the thermal electromagnetic field6 and this leads to a surprisingly strong force acting in the opposite direction of the radiation pressure3.
 P. Hamilton, M. Jaffe, P. Haslinger, Q. Simmons, H. Müller, J. Khoury, Atom-interferometry constraints on dark energy,