This project aims at exploring the properties of spinor Bose-Einstein condensates, i.e. condensates formed in several internal states. We work with spin 1 Sodium atoms, with three internal (Zeeman) states. The atoms are trapped in an optical dipole trap and cooled down to form a Bose-Einstein condensate. We use this system to produce and study collective spin states that form in this dilute gas at ultralow temperatures. These states have many similarities with the equilibrium states of interacting spins in solid-state magnetic materials, but also exhibit novel and previously unexplored features.
Various trapping geometries are or will be explored. For instance, tightly focused optical traps realize a “bosonic quantum dot”, where atomic motion is frozen by quantum confinement. In this setting, spin-exchange interactions between the atoms could lead to highly entangled spin states, such as spin-squeezed states or even Schrödinger cat-like states. Another avenue is to look for novel antiferromagnetic phases for bosons in periodic potentials, for instance in a spin 1 chain realized in a one-dimensional optical lattice.
Team: Qu An, Jean Dalibard, Bertrand Evrard, Fabrice Gerbier
Contacts: Fabrice Gerbier, Jean Dalibard
Collège de France, 11 Place Marcelin-Berthelot. 75005 Paris