Dark Matter Axions, Non-Newtonian Gravity and Constraints on them from Recent Measurement of the Casimir Force in the Micrometer Separation Range

TL;DR

This paper uses recent Casimir force measurements to set new constraints on axionlike particles and non-Newtonian gravity, improving previous bounds and discussing future experimental prospects.

Contribution

It introduces novel constraints on axion-nucleon coupling and Yukawa interactions derived from precise Casimir force measurements over a wide separation range.

Findings

Constraints on axion-nucleon coupling are four times stronger than previous limits.

Yukawa interaction constraints are 24 times more stringent than earlier results.

The experiment covers a wide separation range from 0.2 to 8 micrometers.

Abstract

We consider axionlike particles, as the most probable constituents of dark matter, the Yukawa-type corrections to Newton's gravitational law and constraints on their parameters following from astrophysics and different laboratory experiments. After a brief discussion of the results by Prof. Yu. N. Gnedin in this field, we are coming to the recent experiment on measuring the differential Casimir force between Au-coated surfaces of a sphere and the top and bottom of rectangular trenches. In this experiment, the Casimir force was measured over an unusually wide separation region from 0.2 to 8~mcm and compared with the exact theory based on first principles of quantum electrodynamics at nonzero temperature. We use the measure of agreement between experiment and theory for obtaining constraints on the coupling constant of axionlike particles to nucleons and on the interaction strength of Yukawa-type interaction. The obtained constraints on the axion-to-nucleon coupling constant and on the strength of Yukawa interaction are stronger by the factors of 4 and 24, respectively, than those found previously from gravitational experiments and measurements of the Casimir force, but weaker than the constraints following from the differential measurement where the Casimir force was nullified. Some other already performed and planned experiments directed to the search of axions and non-Newtonian gravity are discussed and their prospects are evaluated.