Advances in nuclear spin coherent control, and in SQUID design, for a new measurement of the xenon-129 EDM. 

We present advances in coherent control and SQUID design, which will be used in a new measurement of the xenon-129 EDM targeting 10-100x improvement over the state of the art.  We have developed a novel coherent control protocol, allowing for the first time the creation of robust pulses that can simultaneously control independent, colocated nuclear spin ensembles at the quantum speed limit, and which can be stacked to be insensitive to fluctuations in the background magnetic field at first order.  We have used this protocol to demonstrate state-initialization precision at 99.9%, and suppression of sensitivity to the magnetic holding field.  This is 10x more precise than the previous state of the art, and will directly extend the coherent integration time of helium-xenon comagnetometers by a similar factor from ~300 seconds to ~3000 seconds.  

We also present a new SQUID design with multiple planar gradiometers which can reach ~fT/rt(Hz) noise measurement in a 2 muT background, and with 10 kV applied to the cell.