Quantum disorder powers self-sustaining microwave signal in diamond

Researchers from TU Wien and the Okinawa Institute of Science and Technology have demonstrated that superradiance—a quantum phenomenon where many particles emit energy collectively in a powerful but typically short-lived burst—can be harnessed to produce long-lived, self-sustaining microwave signals without external energy input. Using a diamond crystal embedded with nitrogen-vacancy (NV) centers placed inside a microwave cavity, they observed that after an initial superradiant burst, the system emitted a series of narrow, coherent microwave pulses lasting up to one millisecond. This unexpected persistence arises from spin–spin interactions within the diamond that dynamically redistribute energy among the spins, effectively enabling the system to drive itself through a process called self-induced superradiant masing. This discovery overturns the traditional view that such interactions only introduce noise and destroy coherence in quantum systems. Instead, the chaotic spin dynamics organize themselves to maintain a stable, coherent microwave signal. The ability to generate long-lived, self-sustaining quantum signals has significant implications for practical technologies