title: Test of the gravitational inverse square law at millimeter ranges.
abstract: We report a new test of the gravitational inverse square law at millimeter ranges by using a dual-modulation torsion pendulum. An I-shaped symmetric pendulum and I-shaped symmetric attractors were adopted to realize a null experimental design. The non-Newtonian force between two macroscopic tungsten plates is measured at separations ranging down to 0.4 mm, and the validity of the null experimental design was checked by non-null Newtonian gravity measurements. We find no deviations from the Newtonian inverse square law with 95% confidence level, and this work establishes the most stringent constraints on non-Newtonian interaction in the ranges from 0.7 to 5.0 mm, and a factor of 8 improvement is achieved at the length scale of several millimeters.
authors.affiliation: School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
authors.forename: Shan-Qing
authors.initials: SQ
authors.lastname: Yang
authors.forename: Bi-Fu
authors.initials: BF
authors.lastname: Zhan
authors.forename: Qing-Lan
authors.initials: QL
authors.lastname: Wang
authors.forename: Cheng-Gang
authors.initials: CG
authors.lastname: Shao
authors.forename: Liang-Cheng
authors.initials: LC
authors.lastname: Tu
authors.forename: Wen-Hai
authors.initials: WH
authors.lastname: Tan
authors.forename: Jun
authors.initials: J
authors.lastname: Luo