Microwave Near-Field Quantum Control of Trapped Ions
  Microwave near-field quantum control of spin and motional degrees of freedom of 25Mg+ ions can be used to generate two-ion entanglement, as recently demonstrated in Ospelkaus et al. [Nature 476, 181 (2011)]. Here, we describe additional details of the setup and calibration procedures for these experiments. We discuss the design and characteristics of the surface-electrode trap and the microwave system, and compare experimental measurements of the microwave near-fields with numerical simulations. Additionally, we present a method that utilizes oscillating magnetic-field gradients to detect micromotion induced by the ponderomotive radio-frequency potential in linear traps. Finally, we discuss the present limitations of microwave-driven two-ion entangling gates in our system. 
U. Warring, C. Ospelkaus, Y. Colombe, K. R. Brown, J. M. Amini, M.   Carsjens, D. Leibfried, and D. J. Wineland
quant-ph physics.atom-ph