The return of the spin echo

The return of the spin echo - Credit: C. Hohmann / MCQST

A research team from Garching and Vienna University of Technology discovered a remarkable echo effect that offers exciting new possibilities for working with quantum information.

The 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 cleverly excited 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. Surprisingly, this spin echo does not occur only once, but a whole series of echoes can be detected.

The strong coupling between the atomic spins and the microwave resonator is responsible for the multiple echoes: If the spins of the atoms all point in the same direction in the first echo, this produces an electromagnetic signal.

This opens up new possibilities of how information can be processed with quantum systems.

The work has been published in the journal Physical Review Letters.

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