More than 50 years ago, physicist Sir Roger Penrose proposed a remarkable idea: under the right conditions, it might be possible to extract energy from a rapidly spinning black hole. In his concept, a particle entering the black hole’s ergosphere, a region where spacetime is dragged along by the object’s rotation, could split into two. One fragment would fall into the black hole while the other escaped carrying away more energy than the original particle. Later, physicist Yakov Zel’dovich expanded on this concept, predicting that waves interacting with an object rotating fast enough could also gain energy and become amplified.
Now, researchers at the Advanced Science Research Center at the CUNY Graduate Center (CUNY ASRC) have demonstrated an experimental approach inspired by those long standing theories. Writing in the journal Nature, the team showed that wave amplification can be achieved using a device that simulates extreme rotation without physically spinning.
Synthetic Rotation Recreates Extreme Physics
Instead of rotating an object mechanically, the researchers built a radio frequency device whose properties are rapidly changed across both space and time. This carefully engineered system creates the illusion of ultrafast rotation, reaching effective rotational speeds far beyond what conventional mechanical systems can achieve. By replacing physical motion with synthetic rotation, the researchers overcame challenges that have limited experimental studies of extreme rotational physics for decades.
“Our approach facilitates a new method of wave-matter interaction in which waves with selected rotational properties extract energy from synthetic time-engineered rotation, producing a form of broadband selective amplification,” said principal investigator Andrea Alù, Distinguished Professor and Einstein Professor of Physics at the CUNY Graduate Center and founding director of the CUNY ASRC’s Photonics Initiative.
Lead author Hadiseh Nasari, a post-doctoral researcher with the CUNY ASRC’s Photonics Initiative, said the experiment transforms a long standing theoretical concept into a practical research tool.
“This successful experiment moves ideas about extreme rotational dynamics from theory to practice and creates a versatile experimental platform for exploring a broad range of phenomena at the intersection of astrophysics, wave physics, and quantum science,” said Nasari. “The work has implications for advances in fundamental science and in communications, optics and photonics.”
How the Experiment Worked
The researchers set out to answer a fundamental question: Could electromagnetic waves interacting with a completely stationary device behave as though they were encountering an object rotating at ultrafast speed and draw energy from that synthetic motion?
To investigate, they constructed a ring of electronic resonators whose properties were rapidly adjusted in a carefully synchronized sequence. Although the hardware itself never moved, these timed changes generated a traveling pattern around the ring. As a result, the electromagnetic waves effectively experienced the system as though it were spinning at extraordinary speed.
“Waves with the appropriate rotational characteristics extracted energy from the system and became amplified, reproducing the essential physics of the Penrose-Zel’dovich process,” said co-lead author Hady Moussa, a former PhD student with the CUNY ASRC Photonics Initiative. “Our approach relies on engineered metamaterials that are designed to control how waves propagate.”
Potential Applications Beyond Black Hole Physics
Because synthetic rotation can imitate motion beyond the speed of light, researchers now have a controlled laboratory platform for exploring physical regimes that would otherwise be impossible to study directly. The work creates new opportunities for investigating extreme physics while also pointing toward future advances in wireless communications, optics, photonics, and quantum technologies.
The researchers note that additional work will be needed before these ideas can be translated into practical devices. They also believe the same principles could be applied to photonic and quantum systems, opening new possibilities for controlling light, processing information, and studying wave behavior inspired by some of the universe’s most extreme environments.
The research was supported by the U.S. Department of Defense, the U.S. National Science Foundation, and the Simons Foundation.