title: Search for Screened Interactions Associated with Dark Energy below the 100 μm Length Scale.
abstract: We present the results of a search for unknown interactions that couple to mass between an optically levitated microsphere and a gold-coated silicon cantilever. The scale and geometry of the apparatus enable a search for new forces that appear at distances below 100  μm and which would have evaded previous searches due to screening mechanisms. The data are consistent with electrostatic backgrounds and place upper limits on the strength of new interactions at <0.1  fN in the geometry tested. For the specific example of a chameleon interaction with an inverse power law potential, these results exclude matter couplings β>5.6×10^{4} in the region of parameter space where the self-coupling Λ≳5  meV and the microspheres are not fully screened.
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Rider
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Moore
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Charles P
authors.initials: CP
authors.lastname: Blakemore
authors.affiliation: Department of Physics, École Polytechnique, 91128 Palaiseau, France.
authors.forename: Maxime
authors.initials: M
authors.lastname: Louis
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Marie
authors.initials: M
authors.lastname: Lu
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Gratta