April 13, 2024

Graviton-Like Particles Found in Quantum Experiments

Light probing a chiral graviton mode in a fractional quantum Hall effect liquid. Credit: Lingjie Du, Nanjing University

The results, continuing the legacy of late Columbia professor Aron Pinczuk, are a step toward a better understanding of gravity.

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

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

Uniting Theoretical Physics and Experimental Reality

The ability to study graviton-like particles in the laboratory could help fill critical gaps between quantum mechanics and Einstein’s theories of relativity, resolving a major dilemma in physics and expanding our understanding of the universe.

“Our experiment marks the first experimental confirmation of this concept of gravitons, postulated by pioneering work in quantum gravity since the 1930s, in a condensed matter system,” said Lingjie Du, a former Columbia postdoc and senior author of the paper. .

Quantum metric and its predictions

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

The electrons in a FQHE are subject to what is known as quantum metric, which was predicted to give rise to CGMs in response to light. However, in the decade since quantum metric theory was first proposed for FQHEs, there have been limited experimental techniques to test its predictions.

Aron Pinczuk’s Legacy: Pioneering Quantum Research

For much of his career, Columbia physicist Aron Pinczuk has studied the mysteries of FQHE liquids and worked to develop experimental tools that could probe such complex quantum systems. Pinczuk, who joined Columbia from Bell Labs in 1998 and was a professor of physics and applied physics, passed away in 2022, but his laboratory and former students around the world have continued his legacy. These alumni include paper authors Ziyu Liu, who graduated with her PhD in physics from Columbia last year, and former Columbia postdocs Du, now at Nanjing University, and Ursula Wurstbauer, now at

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