  We propose a method for transferring atoms to a target quantum state for a
multilevel quantum system with sequentially increasing, but otherwise unknown,
energy splitting. This is achieved with a feedback algorithm that processes
off-resonant optical measurements of state populations during adiabatic rapid
passage in real-time. Specifically, we reliably perform the transfer
$|F=2,m_F=2\rangle \rightarrow |1,1\rangle \rightarrow |2,1\rangle$ for a
sample of ultracold $^{87}$Rb in the presence of a random external magnetic
field.

Quantum Physics;Atomic Physics