Atomic Physics Seminars

The spin-1 Haldane chain is the paradigmatic example of symmetry protected topological (SPT) phases, which are characterized by non-local order and edge states. In my talk, I will report on the experimental realization of such a phase using ultracold fermions in optical lattices (arXiv:2103.10421). 

Using the full spin and density resolution of our Fermi-gas microscope, we detect a finite non-local string correlator in the bulk of a Heisenberg two-leg ladder system and image localized spin-1/2 states at its edges. We find the phase to be robust to perturbations that preserve the spin symmetry. 

Going beyond the spin model, we then study the effects of charge fluctuations on the SPT phase in the more general Hubbard ladder. Finally, I will compare the non-local order seen here to spin-charge separation in doped spin-1/2 chains.