Quantum Whisper in Diamond ⚡ экспресс
Physicists have developed a method for ultra-precise readout of an ensemble of NV centers in diamond—promising quantum sensors. By stabilizing the nuclear spins of the environment with a strong magnetic field and employing repeated nuclear-assisted readout, they reduced noise by 3.8 dB below the thermal projection noise level and, for the first time, directly detected the intrinsic quantum fluctuations and correlations of the spins. This transforms projection-noise-level readout into a practical tool for solid-state quantum sensors, paving the way for quantum-enhanced metrology and spin squeezing.
Every elementary particle has its own rotation—spin. These tiny magnetic spinning tops constantly tremble, generating a faint noise. Hearing it is hindered by the din of light used in detectors. But in a diamond with artificial defects—glowing NV centers—scientists found a loophole. Nitrogen atoms near the defects act like stable 'recorders': their nuclei record the trembling of electron spins, ignoring the optical cacophony.
Repeated readout using spectroscopy allowed the useful whisper to accumulate and reduced overall noise by 3.8 decibels—approaching the fundamental quantum limit. For the first time, correlations between spins appeared without distortion: how they 'talk' to each other. This opens the era of quantum sensors with unprecedented sensitivity. For example, such defects are already able to detect the magnetic field of a single protein molecule—and operate inside a living cell. In perspective—squeezing of spin states for even more precise measurements.
🎯 NV centers can detect the magnetic field of a single protein molecule—they are being explored as nanosensors inside living cells.