A research team led by Chinese scientists has given the first experimental evidence pointing to the existence of gravitons, theoretical particles believed to mediate the force of gravity, according to the South China Morning Post (SCMP).
This discovery is a key step toward closing the gap between quantum mechanics and general relativity, two foundations of modern physics that have previously been entirely irreconcilable.
The study, conducted in partnership with experts from Nanjing University in eastern China, the United States, and Germany, entailed depositing a tiny layer of semiconductor under harsh conditions. By chilling the semiconductor to near absolute zero and providing a magnetic field 100,000 times stronger than Earth’s, the team was able to excite the semiconductor’s electrons to travel in tandem. This collective motion caused the electrons to spin in a way that was consistent with graviton predictions, despite the fact that the particle’s existence was not confirmed.
“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 principal author from Nanjing University, told state news agency Xinhua, according to SCMP.
This work, published in the journal Nature, opens up new possibilities for the search for gravitons in laboratory settings.
The graviton, if it exists, is thought to be massless and capable of traveling at the speed of light, embodying the force of gravity. However, scientists have yet to observe it directly, if the team’s findings are correct. Du identified an excitation phenomenon in 2019 while working as a postdoctoral researcher at Columbia University, which led to the recent findings. This incident sparked speculation among theoretical physicists regarding the possibility of detecting gravitons.
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The experiment’s success was the product of multinational collaboration. Princeton University researchers prepared high-quality semiconductor samples, while Du and his colleagues built a one-of-a-kind laboratory over the course of three years to conduct the experiment. This equipment allowed the researchers to work at – 273.1 degrees Celsius while capturing particle excitations as feeble as 10 gigahertz and detecting their spin.
When a flat sheet of gallium arsenide semiconductor was exposed to these severe circumstances, it showed a phenomena known as the quantum Hall effect. This highlights not only the complexities of carrying out high-precision experiments, but also the devotion and international collaboration required to expand our understanding of the universe.
As the SCMP revealed, there are numerous imokications. Confirming the existence of gravitons would not only support an old idea, but also provide new insights into the fundamental forces that control our universe. The work serves as a link between the vast realm of general relativity and the microscopic world of quantum mechanics, potentially unlocking many puzzles of modern physics and leading to further discoveries.