Séminaires du Groupe de Travail "Quantum Information and Quantum Computing": Nicolas Treps (Laboratoire Kastler Brossel) & Giuseppe Patera (Laboratoire PhLAM)phlam Vie du laboratoire Séminaire
14:00-14:45: Nicolas Treps (Laboratoire Kastler Brossel). Quantum metrology and optical modes, from precisionmeasurement to entanglement witness.
In this lecture, we will study how classical modal decomposition of light can lead to measurement reaching the quantum Cramér Rao bound. We will demonstrate how it can be experimentally implemented and how theoretical limit be derived in the presence of experimental imperfections. We will then explore the use of non classical sources and their importance in measurement sensitivity. Finally, we will take the opposite point of view, and study how the sensitivity of a quantum states to parameter change can be use as a witness for entanglement, and make the link between quantum Fisherinformation and quantum steering.
15:00-15:45: Giuseppe Patera (Laboratoire PhLAM). Elements of one-way quantum computation and its application in quantum optics
One-way Quantum Computation (QC) is an equivalent alternative to the circuit model of universal QC. One-way QC starts from a "cluster state", an entangled qubit lattice which contains all the entanglement that can ever be needed by a quantum algorithm. It then proceeds solely by single-qubit measurements which inform feed-forward unitaries on the lattice neighbours. In this presentation I will review few basics facts about one-way quantum computation and I willdiscuss its physical implementation in the domain of quantum optics in particular through physical observables with a continuous spectrum of eigenvalues.