Optical Control of Interactions in an Energy-Space Spin Lattice

A spin lattice in energy-space is created by a weakly-interacting Fermi gas, which conserves the single-atom energy states over long time scales. Forward scattering produces effective long-range site-to-site couplings, which we control using optical fields. We demonstrate optical tuning of the site-to-site couplings by inducing spin waves over timescales of hundreds of milliseconds. This optically-controlled many-body system serves as a new platform for simulations of spin lattices and studies of information scrambling.