Liu Lab



Research Projects



Sodium Spinor Bose-Einstein Condensate (BEC)




An atomic Bose-Einstein condensate (BEC) is a state where all atoms have a single collective wavefunction for their spatial degrees of freedom. The key benefit of spinor BECs is the additional spin degree of freedom. Together with Feshbach resonances and optical lattices, spinor BECs constitute a fascinating collective quantum system offering an unprecedented degree of control over such parameters as spin, temperature, and the dimensionality of the system. The interesting interactions in spinor BECs are interconversion among multiple spin states and magnetic field interactions (or microwave dressing field interactions) characterized by the quadratic Zeeman effect. F = 1 spinor BECs have been applied to study antiferromagnetic interactions with Sodium(Na) atoms and ferromagnetic interactions with Rubidium(Rb) atoms.Theoretical work shows that it is possible to manipulate the phase-space topology and dynamics of the Na system in ways not possible in ferromagnetic systems. While the Rb system is well studied in a number of research groups, the Na system is less explored and only a handful of groups worldwide are even capable of performing studies on it.


A coherent spin-state is an unentangled state with all spins aligned in the same direction, while the spin degrees of freedom of atoms become entangled in spin-squeezed states. Spinor BECs provide an opportunity to entangle a large collection of atoms at once. In our group, we will apply a sodium spinor BEC to generate massive entanglement in the vicinity of Dicke states, and to create spin squeezing via collectively coupling atoms to a light field with a quantum non-demolition measurement. This research is both of fundamental interest for advancing our understanding of quantum physics, and of technological significance.




We gratefully acknowledge financial support of our research from: