Gauss constrained basis for SU(N) Lattice Gauge Theory with Tensor Networks

We construct a basis for (d + 1) dimensional SU(N) Kogut-Susskind Lattice Gauge Theory (LGT) with fundamental staggered fermions in which all gauge constraints are explicitly enforced by extending the lattice Hilbert space so that all degrees of freedom may be localized at the vertices, which allows the imposition of the Gauss law at each vertex.

We present a tensor network formulation of (1 + 1) SU(N) LGT using the Gauss constrained basis, and test our approach by calculating the ground state energy and entanglement entropy for (1 + 1) SU(2).

Our numerical results support recent discussions in the literature that only the full entanglement entropy constructed on an extended lattice Hilbert space correctly recovers the CFT central charge in the continuum limit.