WrathfulSpatula
commented
3 years ago Carrying it this far, it probably makes sense to check X/Y/Z basis probability under the assumption that the state is pure and separable and to reconstruct the state from those 3 values and the assumptions.
Single separable bits do tend to stay in RX and RY directions, it turns out. To an extent, this is an artifact of benchmark gate sets, but those gate sets should at least have very uniform coverage on the single qubit subspaces within them.