Generation and detection of gravitational waves at microwave frequencies by means of a superconducting two-body system

TL;DR

This paper proposes a superconducting two-body system as a novel method to generate and detect gravitational waves at microwave frequencies, enabling potential observations of early universe signals and Earth interior communications.

Contribution

It introduces a superconducting sphere-ring system capable of converting gravitational waves into electromagnetic signals with high efficiency, leveraging low-temperature superconductivity.

Findings

The system can potentially detect gravitational waves at microwave frequencies.

Loss-free wave conversion is feasible at low temperatures due to superconductivity.

Practical Hertz-like experiments could enable new gravitational wave observations.

Abstract

The 2-body system of a superconducting sphere levitated in the magnetic field generated by a persistent current in a superconducting ring, can possibly convert gravitational waves into electromagnetic waves, and vice versa. Faraday's law of induction implies that the time-varying distance between the sphere and the ring caused by the tidal force of an incident gravitational wave induces time-varying electrical currents, which are the source of an electromagnetic wave at the same frequency as the incident gravitational wave. At sufficiently low temperatures, the internal degrees of freedom of the superconductors are frozen out because of the superconducting energy gap, and only external degrees of freedom, which are coupled to the radiation fields, remain. Hence this wave-conversion process is loss-free and therefore efficient, and by time-reversal symmetry, so is the reverse process. A Hertz-like experiment at microwave frequencies should therefore be practical to perform. This would open up observations of the gravitational-wave analog of the Cosmic Microwave Background from the extremely early Big Bang, and also communications directly through the interior of the Earth.