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Pushing the limits of measurement accuracy with quantum sensors


Quantum sensors can reach sensitivity levels that are impossible to reach according to the laws of classical physics we know from our everyday lives. Such sensitivity levels can only be reached if we delve into the world of quantum mechanics with all of its fascinating characteristics. One such characteristic is the phenomenon of superposition, which states that objects can be in two places at once and that an atom can occupy two different energy levels at the same time.

The experiment can be visualized as the quantum-mechanical version of a simple pendulum. In this case, the pendulum’s maximum deflection and number of oscillations per second are the two optimized measurands. Here, the pendulum has been realized via a single magnesium ion trapped in an ion trap.

Scientists at PTB’s QUEST Institute and at Leibniz Universität Hannover, together with researchers at the Institute for Theoretical Physics at Leibniz Universität Hannover and at the National Institute of Optics in Florence, Italy, have developed a method that exploits quantum-mechanical states to determine two quantities more accurately than classical states allow. In this way, high-precision spectroscopic investigations performed on molecules can be used to investigate a possible interaction between conventional and dark matter. This measurement principle, which has been demonstrated for the first time, could also improve the resolution in optical interferometers such as gravitational wave detectors, thus enabling deeper insight into the early days of the universe. They have reported on their findings in Nature Communications.