Gravitons ... the quest begins :)

Light probing a chiral graviton mode in a fractional quantum Hall effect liquid. 

Credit: Lingjie Du, Nanjing University

For over 100 years, researchers have tried in vain to marry general relativity to quantum mechanics without success as the science of the very large doesn't play nice with the science of the very small yet both entities give rise to the existence in which all things reside. With this being said, the possibility gravitons, the theoretical force carrier of gravity, may exist after all, a revelation potentially leading to the holy grail of integrating relativity to quantum into one theory capable of explaining how reality functions at deep level, may finally be at hand.

Spacetime curvature schematic - Relativity

Abstract image of quantum probability. (Image credit: agsandrew via Shutterstock)

A research team led by Chinese scientists has provided the first experimental evidence hinting at the existence of gravitons, theoretical particles believed to mediate the force of gravity, according to the South China Morning Post (SCMP),

This discovery marks a significant step towards bridging the gap between quantum mechanics and general relativity, two pillars of modern physics that have remained largely incompatible.

“Our work has shown the first experimental substantiation of gravitons in condensed matter since the elusive particle was conceptualized in the 1930s,” Du Lingjie, the study’s lead author from Nanjing University, told state news agency Xinhua, as reported by SCMP.

This experiment, which was published in the journal Nature, opens new avenues for the search for gravitons in laboratory settings.

The graviton, if it exists, is theorized to be massless and capable of traveling at the speed of light, embodying the force of gravity. Yet, its direct observation has eluded scientists until now, if the team’s research holds up. The recent findings stem from an excitation phenomenon discovered in 2019 when Du was a postdoctoral researcher at Columbia University. This phenomenon led theoretical physicists to speculate about the potential detection of gravitons.

Some details ...

Graviton modes and inelastic light scattering. 

Credit: Nature (2024). DOI: 10.1038/s41586-024-07201-w

A team of scientists from Columbia, Nanjing University, Princeton, and the University of Munster, writing in the journal Nature, have presented the first experimental evidence of collective excitations with spin called chiral graviton modes (CGMs) in a semiconducting material.

A CGM appears to be similar to a graviton, a yet-to-be-discovered elementary particle better known in high-energy quantum physics for hypothetically giving rise to gravity, one of the fundamental forces in the universe, whose ultimate cause remains mysterious.

The team discovered the particle in a type of condensed matter called a fractional quantum Hall effect (FQHE) liquid. FQHE liquids are a system of strongly interacting electrons that occur in two dimensions at high magnetic fields and low temperatures. They can be theoretically described using quantum geometry, emerging mathematical concepts that apply to the minute physical distances at which quantum mechanics influences physical phenomena.

One of the techniques Pinczuk established was called low-temperature resonant inelastic scattering, which measures how light particles, or photons, scatter when they hit a material, thus revealing the material's underlying properties.

And so it begins ...