Dr Sander Vermeulen

Trosolwg

I work on fundamental physics research using interferometry experiments. My research is focused on detecting quantum gravity phenomena and dark matter using optical interferometers.

I am part of a team building twin table-top laser interferometers here at Cardiff University. With these interferometers, we aim to detect signatures of holographic quantum gravity. The experiment will also be sensitive to high-frequency gravitational waves, and certain hypothetical dark matter particles.

_{How can we observe quantum gravity with interferometers?}

Gravity has never been observed to have quantum mechanical properties. Einstein's theory of General Relativity tells us gravity can be explained not as a force, but by considering the movement of matter in a curved space-time. At its core, space-time describes how distances and lengths depend on the presence of matter and energy. We know matter and energy follow the laws of quantum mechanics. Therefore, it is thought that space-time (and therefore measurements of distances) must be quantum-mechanical as well. Laser interferometry is the most precise method for measuring distances, and state-of-the-art interferometers can detect length fluctuations as small as 10^-19 meters. By measuring distances at this extraordinary precision, we hope to observe signatures of the quantum nature of space-time. This would provide the first experimental evidence to inform a theory of quantum gravity.

_{How can we detect dark matter with interferometers?}

Until recently, it was widely believed that dark matter was composed of heavy elementary particles. These were not discovered despite a multitude of efforts, and scientists are now turning to alternative theories to explain dark matter. A recent theory says that dark matter is actually something called a scalar field, which would behave as invisible waves bouncing around galaxies, including our own Milky Way. Scalar field dark matter waves would pass right through the Earth and our instruments, but as they do so, would cause objects such as mirrors to vibrate ever so slightly. Vibrations of mirrors would disturb the beams of light in interferometers in a particular way characteristic of dark matter, which is something we should be able to detect, depending on the exact properties of that dark matter.