Hello! I see that most experiments applying quantum computing techniques for high precision spectroscopy use a quadrupole trap. I don't know much about the experimental implementation of these kind of traps, so any help (or suggested paper) would be appreciated, but I was wondering how well can one control the electric field at the given ion? In a quadrupole trap, you have both static and RF fields, and given that they are not too long, you would also probably have edge effects leaking inside the trap (no idea how big that effect would be). Also in these experiments they don't mention anything about the xy motion of the ions (i.e. perpendicular to the central axis). Wouldn't that motion also disturb the energy levels? Can someone help me understand a bit how well (and how) can these fields be controlled in these kind of traps? Thank you!