Freiburg 2019 – scientific programme

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FM: Fall Meeting

FM 76: Entanglement: Spectroscopy

FM 76.1: Invited Talk

Thursday, September 26, 2019, 14:00–14:30, 1015

Enhancing the precision of measurements with entanglement — •Manuel Gessner — Département de Physique, École Normale Supérieure, PSL Université, CNRS, 24 Rue Lhomond, 75005 Paris, France — Laboratoire Kastler Brossel, ENS-PSL, CNRS, Sorbonne Université, Collège de France, 24 Rue Lhomond, 75005 Paris, France

Our fundamental understanding of Nature as well as technological developments depend crucially on our ability to implement measurements with better precision. Currently, spectroscopy of atomic frequencies yields some of the most precise measurements and allows us to define time standards with atomic clocks. These measurements are soon expected to reach a classical resolution limit, determined by quantum projection noise, that can only be overcome by making use of quantum strategies. In this talk, we will present an overview of quantum-enhanced methods to improve the sensitivity of intereferometric measurements, such as Ramsey spectroscopy. We will see how the sensitivity of general quantum states can be quantified and how suitable observables for precision measurements can be determined under realistic constraints. Furthermore, we show how entanglement witnesses can be constructed by deriving upper limits on the sensitivity of separable quantum states. We will discuss applications in atomic and photonic experiments.