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Microwave quantum logic gates for trapped ions



Dietrich G. Leibfried, Christian Ospelkaus, Ulrich J. Warring, Yves Colombe, Kenton R. Brown, J. M. Amini, David J. Wineland


Achieving control over physical systems at the quantum level is a goal shared by scientific fields as diverse as metrology, information processing, simulation and chemistry. For trapped atomic ions, the quantized motional and internal degrees of freedom can be coherently manipulated with laser light. Similar control is difficult to achieve with radio frequency or microwave radiation because the essential coupling between internal degrees of freedom and motion requires significant field changes over the extent of the atoms' motion. The required field gradients are negligible at these frequencies for freely propagating fields; however, stronger gradients can be achieved in the near-field generated by microwave currents in structures smaller than the free-space wavelength. In the experiments reported here, we coherently manipulate the internal quantum states of the ions on time scales of 20 ns. We also generate entanglement between the internal degrees of freedom of two atoms, with a gate operation that would enable general quantum computation. We implement this gate through the magnetic field gradients from microwave currents in electrodes that are directly integrated into the micro-fabricated trap structure and create an entangled state with fidelity 76(3)%. This approach, where the quantum control mechanism is integrated into the trapping device in a scalable manner, can potentially benefit quantum information processing, simulation and spectroscopy.


microwave control, quantum information processing, trapped ions


Leibfried, D. , Ospelkaus, C. , Warring, U. , Colombe, Y. , Brown, K. , Amini, J. and Wineland, D. (2011), Microwave quantum logic gates for trapped ions, Nature, [online], (Accessed July 19, 2024)


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Created August 11, 2011, Updated February 19, 2017