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CCD image of the first qubyte, comprising eight calcium ions in an electromagnetic trap, observed at the University of Innsbruck. The separation between the ions is 5 μm. The ions are in a vacuum, to minimize sources of decoherence, and long-range electrostatic forces between them ensure quantum entanglement. They are detected by fluorescence caused by laser pulses. (All images courtesy H Häffner, University of Innsbruck.)