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Quantum-enhanced sensing of displacements and electric fields with large trapped-ion crystals



Kevin Gilmore, Matthew Affolter, Judith Jordan, Diego Barberena, Robert Lewis-Swan, Ana Maria Rey, John J. Bollinger


Developing the isolation and control of ultracold atomic systems to the level of single quanta has led to significant advances in quantum sensing, yet demonstrating a quantum advantage in real world applications by harnessing entanglement remains a core task. Here, we realize a many-body quantum-enhanced sensor to detect weak displacements and electric fields using a large crystal of approx. 150 trapped ions. The center of mass vibrational mode of the crystal serves as high-Q mechanical oscillator and the collective electronic spin as the measurement device. By entangling the oscillator and the collective spin before the displacement is applied and by controlling the coherent dynamics via a many-body echo we are able to utilize the delicate spin-motion entanglement to map the displacement into a spin rotation such that we avoid quantum back-action and effectively cancel detrimental thermal noise. We report quantum enhanced sensitivity to displacements of 8.8 + or- } 0.4 dB below the standard quantum limit and a sensitivity for measuring electric fields of 240 + or-} 10 nVm^-1^ in 1 second (240 nVm^-1^/√HZ).
Science Magazine


electric field sensing, entanglement, many body, quantum sensing, trapped ions


Gilmore, K. , Affolter, M. , Jordan, J. , Barberena, D. , Lewis-Swan, R. , Rey, A. and Bollinger, J. (2021), Quantum-enhanced sensing of displacements and electric fields with large trapped-ion crystals, Science Magazine, [online],, (Accessed May 23, 2024)


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Created August 6, 2021, Updated November 29, 2022