Surprising effect in a system for processing quantum information

A team of researchers from the Technical University of Munich (TUM), TU Wien (Vienna University of Technology) and the Bavarian Academy of Sciences and Humanities have discovered a remarkable echo effect – this effect presents exciting, new opportunities for working with quantum information.

Small particles can have an angular momentum that points in a certain direction – this is known as spin. This spin can be manipulated using a magnetic field. This principle, for example, is the basic idea behind magnetic resonance imaging as used in hospitals.

An international research team has now discovered a surprising effect in a system that is particularly well suited for processing quantum information: the spins of phosphorus atoms in a piece of silicon, coupled to a microwave resonator.

If these spins are expertly stimulated with microwave pulses, a so-called spin echo signal can be detected after a certain time – the injected pulse signal is re-emitted as a quantum echo.

Amazingly, this quantum echo doesn’t occur only once, but a whole series of echoes can be detected. This opens up new possibilities of how information can be processed with quantum systems.

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Source: “The Return of the Spin Echo”, Technical University Munich