Quantum Computation and Information Seminar 

22/11/2019, 10:00 — 11:00 — Room P3.10, Mathematics Building
Wolfgang Dür, University of Innsbruck

Macroscopic quantum states: applications and fundamental limitations

The creation of ever larger quantum states that are in a coherent superposition is an experimental challenge of fundamental and practical interest. We report on attempts to characterize such superposition states, and on fundamental limitations to prepare, maintain and detect them. This includes general results on fragility of all macroscopic quantum states under noise, and the need of tremendous measurement devices to detect them. We also consider applications of such states in the context of quantum metrology, and show that noise and imperfections limit the achievable quantum advantage. We discuss methods such as dynamical control or quantum error correction that allow one to overcome some of these limitation, and present noise-resilient methods for optimal sensing of non-local quantities using distributed sensors.