New directions for gravitational wave physics via "Millikan oil drops"

TL;DR

This paper proposes a novel quantum transducer using levitated superfluid helium drops coated with electrons to convert electromagnetic radiation into gravitational waves efficiently, enabling potential new experiments in gravitational wave physics.

Contribution

It introduces a new method employing Millikan oil drops as quantum transducers for electromagnetic and gravitational wave conversion at microwave frequencies.

Findings

Predicted large scattering cross sections at Mie resonance.

Proposed a Hertz-like experiment for gravitational wave detection.

Discussed practical implementation with superconducting spheres.

Abstract

"Millikan oil drops" are drops of superfluid helium coated with electrons, and levitated in a strong, inhomogeneous magnetic field. When the temperature of the system becomes very low compared to the cyclotron gap energy, the system remains in its quantum ground state. Two such levitated charged drops can have their charge-to-mass ratio critically adjusted so that the forces of gravity and electricity between the drops are in balance. Then it is predicted that the amount of scattered electromagnetic and gravitational radiation from the drops are equalized, along with these two kinds of forces. The cross sections for the scattering of the two kinds of radiation can become large, hard-sphere cross-sections at the first Mie resonance, due to the hard-wall boundary conditions on the surfaces of the spheres for both kinds of radiations. An efficient quantum transduction process between electromagnetic and gravitational radiation by such a pair of drops is predicted at microwave frequencies, and a Hertz-like experiment is proposed. A more practical implementation of these ideas to use pairs of levitated, charged superconducting spheres is briefly discussed.