Deterministic quantum state transfer of atoms in a random magnetic field

Abstract

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 $|F=2,m_F=2⟩\to |1,1⟩\to |2,1⟩$ for a sample of ultracold ${}^{87}$Rb in the presence of a random external magnetic field.