Efficient Basis Formulation for (1 + 1)-Dimensional SU(2) Lattice Gauge Theory: Spectral Calculations with Matrix Product States

We propose an explicit formulation of the physical subspace for a (1$+$1)-dimensional SU(2) latticegauge theory, where the gauge degrees of freedom are integrated out. Our formulation is completelygeneral, and might be potentially suited for the design of future quantum simulators. Additionally, it allowsfor addressing the theory numerically with matrix product states. We apply this technique to explore thespectral properties of the model and the effect of truncating the gauge degrees of freedom to a small finitedimension. In particular, we determine the scaling exponents for the vector mass. Furthermore, we alsocompute the entanglement entropy in the ground state and study its scaling towards the continuum limit