CUNY researchers demonstrate Penrose-Zel'dovich energy extraction in lab analogue

Researchers at the City University of New York have experimentally demonstrated an analogue of the Penrose-Zel'dovich process, a theoretical mechanism by which energy can be extracted from a rotating black hole's ergosphere. The study was published in Nature. The Penrose process, proposed by physicist Roger Penrose in 1969, predicts that particles entering the ergosphere of a rotating black hole can escape with more energy than they entered with, drawing on the black hole's rotational energy. Physicist Yakov Zel'dovich later proposed that waves scattered off a rapidly rotating cylinder could exhibit similar amplification. Since real black holes are inaccessible, the CUNY team led by physicist Hadiseh Nasari used modulated radio waves to simulate the extreme rotational dynamics of a black hole's ergosphere. The researchers applied Floquet theory, a mathematical framework for analyzing periodic systems, to show that waves with specific rotational characteristics extracted energy from the system and became amplified. "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," Nasari said. The experiment does not produce usable energy but provides a laboratory platform for studying physics that would otherwise require proximity to a rotating black hole. The research was conducted at CUNY and published in Nature.