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Quantum metrology uses quanta — individual packets of energy — for setting the standards that define units of measurement and for other high-precision research. Quantum mechanics sets the ultimate limit on the accuracy of any measurement. Quantum metrology, therefore, uses quantum effects to enhance precision beyond that possible through classical approaches.
The quantum anomalous Hall effect holds promise for quantum resistance metrology, but has been limited to low operating currents. A measurement scheme that increases the effect’s operational current is now demonstrated — a scheme that could also be used more generally to improve the performance of existing primary quantum standards of resistance based on the conventional quantum Hall effect.
In this study, the authors propose a generic machine-learning-assisted framework to improve the overall performance of quantum sensing application. In the context of an atomic force sensor, this entirely data-driven approach, which involves generating the digital twinning of experimental data, demonstrates an order of magnitude improvement in sensitivity compared to conventional protocols.
Ultracold atoms are a well-established platform for quantum sensing and metrology. This Review discusses the enhanced sensing capabilities that molecules offer for a range of phenomena, including symmetry-violating forces and dark matter detection.
The authors demonstrated an unprecedented level of polarization squeezing of light generated by an atomic ensemble, and a new regime of continuous quantum measurements on a macroscopic material oscillator.
The quantum anomalous Hall effect holds promise for quantum resistance metrology, but has been limited to low operating currents. A measurement scheme that increases the effect’s operational current is now demonstrated — a scheme that could also be used more generally to improve the performance of existing primary quantum standards of resistance based on the conventional quantum Hall effect.
Quantum technologies change our notion of measurement. Chenyu Wang elaborates on how quantum squeezing enhances the precision of gravitational-wave interferometers.
Optical atomic clocks are extremely accurate sensors despite the poor use of their resources. A parallel quantum control approach might help to optimize the resources of optical atomic clocks, which could lead to an exponential improvement in their performance.
In principle, quantum entanglement gives advantages in radar detection even under noisy and lossy operating conditions. More than a decade after the proposal, the predicted quantum advantage has finally been demonstrated at microwave frequencies.
Controlling the spatial distribution of optically active spin defects in solids is a long-standing goal in the quantum sensing and simulation communities. Measurements of the many-body noise generated by the spins were used to verify that a highly coherent and strongly interacting quantum spin system was confined to two dimensions within a diamond substrate.