Using graphene conductors to enhance the functionality of atom chips

We show that the performance and functionality of atom chips can be transformed by using graphene-based van der Waals heterostructures to overcome present limitations on the lifetime of the trapped atom cloud and on its proximity to the chip surface. Our analysis involves Green's-function calculations of the thermal (Johnson) noise and Casimir-Polder atom-surface attraction produced by the atom chip. This enables us to determine the lifetime limitations produced by spin flip, tunneling, and three-body collisional losses. Compared with atom chips that use thick metallic conductors and substrates, atom-chip structures based on two-dimensional materials reduce the minimum attainable atom-surface separation to a few hundred nanometers and increase the lifetimes of the trapped atom clouds by orders of magnitude so that they are limited only by the quality of the background vacuum. We predict that atom chips with two-dimensional conductors will also reduce spatial fluctuations in the trapping potential originating from imperfections in the conductor patterns. These advantages will enhance the performance of atom chips for quantum sensing applications and for fundamental studies of complex quantum systems.