Berlin 2024 – scientific programme

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QI: Fachverband Quanteninformation

QI 5: Entanglement Theory

QI 5.9: Talk

Monday, March 18, 2024, 17:30–17:45, HFT-FT 101

Sequential Weak Measurements for Generating Multipartite Entangled States — •Trinidad B. Lantaño, Dayou Yang, Koenraad Audenaert, Susana Huelga, and Martin Plenio — Institut für Theoretische Physik, Albert-Einstein-Allee 11, Universität Ulm 89069, Germany

We propose a state preparation protocol based on sequential measurements of a central spin coupled with a spin ensemble, and investigate the usefulness of the generated multi-spin states for quantum enhanced metrology. Remarkably, our protocol allows for the generation of highly entangled spin states, devoid of the necessity for non-linear spin interactions. The metrological sensitivity of the resulting state surpasses the standard quantum limit, reaching the coveted Heisenberg limit under symmetric coupling strength conditions. Additionally, we study the relevant case where coupling strengths are not symmetric, obtaining a specific time length for the preparation protocol where optimal sensitivity is achieved. Our results establish a new approach for the generation of large-scale, entangled states for quantum enhanced metrology within current experimental capabilities.

Keywords: Heisenberg scaling; sequential weak measurements; central spin