Researchers propose way to “see” gravity for the first time

Key Takeaway: Solving the mystery of how gravity operates on the smallest scales governed by quantum mechanics has been a long-standing challenge for physicists. While we have a good understanding of gravity’s effects on large objects like planets and stars, its behavior at the subatomic level remains elusive.

The prevailing theory suggests that gravity is mediated by hypothetical particles called gravitons, similar to how electromagnetism is mediated by photons. However, detecting gravitons has been a formidable task due to their weak interaction with matter, akin to neutrinos.

A recent breakthrough by Igor Pikovski’s team, published in Nature Communications, presents a novel approach to potentially detect gravitons using quantum sensing techniques. This development could pave the way for observing the elusive force of gravity.

Pikovski and his colleagues drew inspiration from Einstein’s groundbreaking work on the photoelectric effect to devise a method for detecting gravity. By applying the concept of quantized energy exchange between light and matter, they propose a similar mechanism for gravity detection.

PhD student Germain Tobar, a co-author of the study, elaborated on the team’s innovative approach: “We have devised a method akin to the photoelectric effect, utilizing acoustic resonators and gravitational waves passing through Earth. This ‘gravito-phononic’ effect could revolutionize our understanding of gravity.”

The proposed experiment involves observing the behavior of a massive cylinder composed of 4,000-pound aluminum bars at its quantum energy ground state. When a gravitational wave interacts with the cylinder, it is expected to induce subtle distortions, leading to detectable energy fluctuations.

By monitoring the vibrations of the cylinder, researchers anticipate capturing discrete energy changes, symbolizing the absorption or emission of gravitons from passing gravitational waves. This method, however, requires exceptionally strong gravitational events for meaningful observations.

To enhance their chances of success, the team plans to leverage major astronomical occurrences like neutron star collisions, such as the notable 2017 event, to provide sufficient gravitons for detection. They also intend to collaborate with gravitational wave observatories like LIGO for improved sensitivity.

Co-author Thomas Beitel explained the experimental setup: “We synchronize our detector with LIGO’s gravitational wave detections to correlate quantum jumps in our system with external gravitational influences. This coordination with LIGO, the world’s premier gravitational wave observatory, is crucial for our research.”

Despite the technical complexities involved, the researchers acknowledge the significance of their work in pushing the boundaries of quantum sensing with unprecedented mass scales.