  We numerically analyze the feasibility of a platform-neutral, general
strategy to perform quantum simulations of fermionic lattice field theories
under open boundary conditions. The digital quantum simulator requires solely
one- and two-qubit gates and is scalable since integrating each Hamiltonian
term requires a finite (non-scaling) cost. The exact local fermion encoding we
adopt relies on auxiliary $\mathbb{Z}_2$ lattice gauge fields by adding a pure
gauge Hamiltonian term akin to the Toric Code. By numerically emulating the
quantum simulator real-time dynamics, we observe a timescale separation for
spin- and charge-excitations in a spin-$\frac{1}{2}$ Hubbard ladder in the
$t-J$ model limit. Additionally, we show that such local fermion encoding is
also useful in tensor network numerical simulations.
