Kvantimetrologialle

Kvantimetrologialle, or quantum metrology, is the field that investigates how quantum phenomena can enhance measurement precision beyond classical limits. By using nonclassical states of light and matter—such as entangled photons, squeezed light, or superposed atomic states—quantum metrology aims to reduce statistical uncertainty in parameter estimation. Two central concepts are the Standard Quantum Limit (SQL), arising from independent probes, and the Heisenberg limit, which can be approached with entanglement and other quantum resources. Techniques include quantum-enhanced interferometry, Ramsey spectroscopy, and quantum Fisher information analysis used to optimize resources. Applications include optical clocks and atomic clocks for timekeeping, frequency standards, gravimetry, magnetometry, and precision spectroscopy; quantum-enhanced sensors are also used in gravitational wave detectors and navigation. Challenges: maintaining coherence in noisy environments, loss, scalable generation of high-fidelity quantum states, and integration with practical devices. Impact and outlook: progress is enabling more precise time standards, navigation systems, geodesy, and fundamental tests of physics. See also: quantum sensing, quantum optics, atomic clocks.