# Presentation: 250610

- Presentation for the American Physical Society Conference
- by Stephen Minter
- October 26, 2007

- Experiments at UC Merced at the interface of

- Quantum Mechanics

- and

- General Relativity

**Production and Detection of Gravitational Radiation by a Two-Body Superconducting System**

## Outline

- Reflections of high-frequency gravity waves at the boundaries of Type I superconductors
- Conversion from electromagnetic radiation to gravitational radiation and vice-versa
- Applications to engineering, astronomy, and mathematics.

## The effect of a gravity wave

- Low-power gravitational radiation at microwave frequencies creates tidal quadrupole forces that oscillate in time

## Local observer and distant observer

- The local observer **does not see** the oscillations because the test particles are moving along* with* space, not moving *through* space.
- Locally, there is zero acceleration.
- Only the observer at infinity can see the relative motion between the test particles.

## The London moment:  An example of how superconductors and normal metals act differently in the presence of acceleration fields

## What gives rise to reflection of gravity waves?

- The gravito-electric field is due to mass “charge,” while the gravito-magnetic field is due to mass currents.
- The infinite conductivity of superconductors allows total reflection of electromagnetic waves.
- This infinite conductivity may allow total reflection of gravity waves (due to the gravito-magnetic component) because the Cooper pairs carry mass as well as charge.

## Normal metal and superconductor in the presence of a gravito-electric field

## Superconductor in the presence of a gravito-magnetic field

## Superconductor in the presence of a gravito-magnetic field

- While the superconductor itself is accelerating due the tidal gravitational force, the Cooper pairs are not moving with respect to the center of mass.
- This effect (London moment) causes currents to flow at the penetration depth scale, creating a magnetic field.
- Mass currents are created along with electrical currents at the coherence length scale, which may cause total reflection of gravitational radiation.

## Why don’t the Cooper pairs move?

- If frequency of gravitational radiation is below the BCS gap frequency, then the system stays adiabatically in the BCS ground state, where
- 	     is constant.  Thus, the velocity of the Cooper pairs is zero.

## Electromagnetic wave reflection vs. gravity wave reflection:  Why don’t gravity waves reflect from the surface of normal conductors?

- 	Reflection coefficient:

- Gravity waves are
- completely reflected

- No normal metal has a
- resistance this small

## Does this mean that “anti-gravity” is possible??!!

- NO.  Only high-frequency, linearly polarized, gravitational radiation can be reflected due to the gravito-magnetic component of the wave.
- The familiar, DC, gravito-electric field due to mass “charge” cannot be counteracted due to the non-existence of negative mass.
- Reflection of high-frequency gravity waves may be possible due to the existence of both positive and negative mass *currents.*

## The two-body superconductor experimental setup

- Magnetic flux is conserved by supercurrents (Lenz’s law).
- Gravity wave oscillates two-body system.
- Oscillations produce detectable TE01 mode EM wave propagation (Faraday’s law).

## Application to engineering:Possible Hertz-like experiment

## Application to astronomy:Gravity waves from the Big Bang

## Application to mathematics: Maxwell-like equations for weak, nearby gravitational fields