Norman Ramsey and Quantum Technology. E. A. Hinds
Quantum behaviour allows us to build devices with extraordinary performance that cannot be achieved using classical components. The key thing that makes this possible is quantum interference. I will start with Norman Ramsey’s seminal idea of using separated oscillatory fields in magnetic resonance experiments. This led to the discovery and measurement of electric and magnetic moments in nuclei, atoms and molecules. Out of this came the atomic clock, based on the interference of the internal states of a Cs atom, which underpins our whole system of units. With the invention of laser cooling, it became possible to control the motional states of trapped ions or atoms, and this is now the basis for a wide range of newer applications, including quantum computation, the study of exotic many-body quantum systems, and the measurement of tiny forces. As an example, I will explain how to measure acceleration using the interference of ultracold atoms. Remarkably, this has applications ranging from the detection of dark energy and dark matter to the navigation of ships and trains. My talk will be shamelessly biased to showcase activities in our own department.