Measurement of Fields and Forces Beyond Standard Quantum Limits

ABSTRACT

Studies of extreme cases within quantum mechanics have always been particularly attractive. What are the limits of measurement precision? How macroscopic can objects be and still demonstrate unique quantum features, such as entanglement? The talk will review our experiments where macroscopic objects are driven deep into the quantum regime. Observation of a motion trajectory in a quantum reference frame with, in principle, unlimited accuracy will be presented. A concept of a reference frame with an effective negative mass required for such observation will be introduced. Sensing of magnetic fields and of mechanical motion beyond standard quantum limits of sensitivity using this concept will be presented. Application of those ideas to gravitational wave detection and magnetic field sensing will be reported.

References

Hybrid quantum network for sensing in the acoustic frequency range. Novikov et al. Nature 643, 955 (2025).

Entanglement-enhanced magnetic induction tomography. W. Zheng, H. Wang, R. Schmieg, A. Oesterle and E. S. Polzik. Phys. Rev. Lett. (2023) 130, 203602.

Entanglement between Distant Macroscopic Mechanical and Spin Systems. Thomas et al. Nature Physics 17, 228–233(2021).

BIOGRAPHY

Eugene Polzik is Professor of Physics at the Niels Bohr Institute, University of Copenhagen where he leads the Quantum Optics Center QUANTOP and the Center for Biomedical Quantum Sensing. His research interests are within quantum physics of matter and light, quantum sensing, and quantum communication. Among his notable results are the measurements of forces and fields not restricted by the Heisenberg uncertainty, demonstration of the quantum teleportation between material objects and of a quantum memory for light, and generation of entanglement between distant material objects. He is a Member of the Royal Danish Academy of Sciences, a Fellow of the American Physical Society, a Fellow of Optica (OSA), and a Knight of the Order of Dannebrog. He is a recipient of Herbert Walther Award of Optica and German Physical Society, Gordon Moore Distinguished Scholar award, Scientific American Research Leadership award, and Danish Association of Academics award.