Quantum Entropic Self-Localization with Ultracold Fermions.

We study a driven, spin-orbit coupled fermionic system in a lattice at the resonant regime where the drive frequency equals the Hubbard repulsion, for which nontrivial constrained dynamics emerge at fast timescales. An effective density-dependent tunneling model is derived, and it is examined in the sparse filling regime in one dimension. The system exhibits entropic self-localization, where while even numbers of atoms propagate ballistically, odd numbers form localized bound states induced by an effective attraction from a higher configurational entropy. These phenomena occur in the strong coupling limit where interactions impose only a constraint with no explicit Hamiltonian term. We show how the constrained dynamics lead to quantum few-body scars and map to an Anderson impurity model with an additional intriguing feature of nonreciprocal scattering. Connections to many-body scars and localization are also discussed.