Measuring bipartite spin correlations of lattice-trapped dipolar atoms

We demonstrate a bipartition technique using a superlattice architecture to access correlations between alternating planes of a mesoscopic array of spin-3 chromium atoms trapped in a 3D optical lattice.
arXiv:2404.10531 (2024) / Phys. Rev. Lett. 133, 203401 (2024)

Using this method, we observe that out-of-equilibrium dynamics driven by long-range dipolar interactions lead to spin anticorrelations between the two spatially separated subsystems. Our bipartite measurements reveal a subtle interplay between the anisotropy of the 3D dipolar interactions and that of the lattice structure, without requiring single-site addressing.

We compare our results to theoretical predictions based on a truncated cumulant expansion and a new cluster semiclassical method that we use to investigate correlations at the microscopic scale. Comparison with a high-temperature analytical model reveals quantum thermalization at a high negative spin temperature.

The spin dynamics take place in a 532 nm 3D anisotropic lattice, which is dominated by a combination of ferromagnetic (FM) and anti-ferromagnetic (AFM) dipolar couplings in the XZ plane. The addition of a infrared (IR) laser at the end of the dynamics creates a double-well structure that gives rise to two spin subsystems A and B.