Measuring Zak phase in room-temperature atoms

In topological insulators, global geometric phases of energy bands determine the existence of unidirectionally propagating edge states, which are immune to local defects, bringing a new stage for designing noise-resilient devices of electrons, photons and atoms. The geometric phase is measured by adiabatically transporting a quantum state through a Brillouin zone, which requires sophisticated quantum control technique. In atoms, such measurement can only be carried out at an extremely low temperature.