NEW YORK. A ring of completely stationary circuitry sitting on a lab table at the City University of New York has done something that previously required a black hole spinning at close to the speed of light. Physicists at the CUNY Advanced Science Research Center have published a study in Nature demonstrating the Penrose-Zel'dovich process in a controlled laboratory environment for the first time, validating a 55-year-old theoretical framework predicting that waves can extract rotational energy from spinning objects and emerge more powerful than when they entered. The team, led by Distinguished Professor of Physics Andrea Alu and postdoctoral researcher Hadiseh Nasari, bypassed the physical impossibility of mechanically spinning matter fast enough to trigger wave amplification by engineering the rotation out of time-modulated electronics rather than moving parts.
The Theory | Penrose, Zel'dovich, and 55 Years of an Untestable Prediction
The experiment is a direct proof of a concept assembled from two separate theoretical contributions in the mid-20th century. In 1969, Sir Roger Penrose theorized that an object entering the ergosphere, the region of warped spacetime fiercely dragged around by a rapidly spinning black hole, could split in two. If one fragment crosses the event horizon, the surviving fragment can escape the gravity well carrying more energy than the original object possessed before entry, effectively stealing rotational kinetic energy from the black hole itself. Two years later, Soviet physicist Yakov Zel'dovich extended this concept from physical objects to electromagnetic waves. He predicted that light or radio waves bouncing off a sufficiently fast-spinning object would absorb its rotational energy and scatter away amplified, a process now called Zel'dovich amplification. The combined framework is the Penrose-Zel'dovich process.
For five decades, testing Zel'dovich amplification in a laboratory was considered physically impossible. To reach the rotational speeds required to amplify an incoming wave, a mechanical object would need to spin so violently that centrifugal forces would exceed the tensile strength of any known material and tear the device apart before the threshold was reached. The physics was never in doubt. The engineering barrier was total. The CUNY ASRC team eliminated the barrier by eliminating the rotation.
The Experiment | Synthetic Rotation Without Moving Parts
The CUNY ASRC team constructed a small ring-shaped network of electronic resonators that remained completely stationary on a laboratory bench. Rather than mechanically spinning the ring, they used varactor diodes, electronic components whose capacitance changes in response to an applied voltage, to rapidly and sequentially modulate the electrical properties of each node around the ring in a precisely calculated temporal sequence. This time-engineered modulation created a traveling electromagnetic wave pattern racing around the stationary ring. To any incoming radio signal, the system behaved as if it were an object spinning at extreme rotational velocities, a condition the researchers termed synthetic rotation.
When the researchers injected a 100-megahertz radio signal into the device and increased the synthetic rotation frequency, the critical transition occurred when the spin frequency crossed a threshold into what the team describes as a negative Doppler-shift regime. Below that threshold, the incoming signal attenuated normally as it passed through the system. Above it, the signal stopped losing energy and began extracting energy from the synthetic rotation instead, emerging from the stationary device measurably and significantly amplified. The device had executed the Penrose-Zel'dovich process on a benchtop, without a spinning object, without extreme temperatures, and without proximity to any astrophysical body.
Applications | Wireless Amplifiers, Radar, and Photonic Computing
Beyond the astrophysical validation, the underlying technology has concrete near-term engineering value. The ability to achieve broadband, selective wave amplification through a completely motionless device opens a design pathway for highly compact and efficient amplifiers in advanced radar arrays and next-generation wireless communication infrastructure. Conventional amplifiers rely on active gain components that introduce noise and consume power. A synthetic rotation amplifier could theoretically achieve amplification with a fundamentally different noise and power profile, particularly attractive for applications in satellite communications, phased array radar, and millimeter-wave 6G infrastructure.
The more transformative long-term application is in photonic computing. The CUNY ASRC team plans to scale the electronic resonator architecture down to work with light rather than radio waves, implementing synthetic rotation in photonic devices that can be fabricated directly onto computer chips. If successful, engineers could use synthetic rotation to precisely control how light propagates through optical processing hardware, potentially enabling faster data routing, lower-loss optical interconnects, and new quantum computing gate architectures that exploit the amplification physics demonstrated in this experiment. For related coverage on quantum physics and orbital science breakthroughs, see OzoneNews on NASA Cold Atom Lab quantum BEC experiments aboard the ISS and the quantum entanglement captured in a strange metal crystal. For more on the current state of space-based physics research, see coverage of the Euclid telescope discovering the universe most ancient quasars and the NASA Swift Observatory rescue mission.