Ultimate limits of quantum measurements
Daniel Braun (Institut für Theoretische Physik, Universität Tübingen)
Quantum enhanced measurements aim at measuring physical quantities with increased precision by using quantum mechanical effects. At the heart of most theoretical efforts in the field lies quantum parameter estimation theory (q-pet), which provides a powerful and general framework for analysing the performance of measurements in the quantum realm. Most of the work has gone into the investigation of the benefits of entangled states, which are, however, limited in the presence of decoherence. In this talk I will give a wider perspective of quantum enhanced measurements, and explore in particular possibilities of quantum enhancement without the use of entanglement. The examples discussed range from the sensitivity of artificial noses, over the measurement of chemical potentials, to measurements of the speed of light. The latter example goes well beyond q-pet, and I will show that the ultimate precision of speed-of-light measurements is set by both quantum and general relativistic effects, offering a new perspective on possible quantum fluctuations of space-time geometry.
***** ATTENTION : le séminaire « théorie de la matière condensée sur le plateau » a lieu au Parc Club, RdC du bât.18-20 *****