Snapshot-based detection of ½-Laughlin states: coupled chains and central charge*

Experimental realizations of topologically ordered states of matter, such as fractional quantum Hall states, with cold atoms are now within reach. In particular, optical lattices provide a promising platform for the realization and characterization of such states, where novel detection schemes enable an unprecedented microscopic understanding.

Here, I discuss how the central charge can be directly measured in current cold atom experiments using the number entropy as a proxy for the entanglement entropy. I present DMRG simulations of Hubbard-interacting bosons on coupled chains subject to a magnetic field. Tuning the inter-chain hopping, we found a transition from a trivial quasi-one dimensional phase to the topologically ordered Laughlin state at magnetic filling factor ν=1/2 for systems of three or more chains. We resolve the transition using the central charge, on-site correlations, momentum distributions and the many-body Chern number. Finally, we propose a scheme to experimentally estimate the central charge from Fock basis snapshots. Related settings will also be discussed.

The model is realizable with current cold atom techniques and the proposed observables pave the way for the detection and classification of a larger class of interacting topological states of matter.