The first measurable quantum system

Quantum computers promise almost unimaginable computational speeds, but creating such futuristic computers has proven to be very difficult. “Normally, every contact with the outer world changes information in a quantum system in a completely uncontrolled manner,” explains Professor Mario Ruben from the Karlsruhe Institute of Technology (KIT) in Germany, who has created the world’s first stable interface capable of reading the quantum state of an atom. Ruben explains the system was created around a metal atom with a protective enclosure that “defines how much the atom sees of the outer world.” When placed between three electric contacts -- which behave like the channels of a transistor, with the voltage of the middle contact influencing the current through the other two -- the complex protects the atom’s measurable spin for up to 20 seconds. Ruben says that he is sure “the results will be of particular importance to spintronics and quantum computing.”