Quantum Phase Diagram of the 2+1D Untruncated SU(2) Lattice Gauge Theory with Dynamical Fermions

Non-Abelian gauge theories with dynamical matter govern the strong interaction and a broad class of strongly correlated quantum systems, yet their ground-state properties remain difficult to obtain from first principles. Using a continuous-group variational Monte Carlo approach that retains the full SU(2) gauge field without truncation, we determine the ground-state behavior of the SU(2) lattice gauge theory with staggered fermions on an Ltimes L square lattice. Treating the magnetic and electric couplings lambda and g² independently, we find a magnetic-flux transition at lambda^ast=-0.040pm 0.005, with no resolvable drift of the transition point as the electric coupling is varied. Along the physical coupling line lambda=4/g², for L=4,6,8, we uncover a gauge-matter delocalization crossover from a flux-disordered regime at strong electric coupling to an ordered unity-flux regime at weak coupling. The chiral condensate, a gauge-invariant Wilson-line meson correlator, and the local color density consistently reveal the emergence of coherent gauge-assisted matter dynamics. Together, these results provide a unified physical picture of how magnetic-flux ordering and fermionic coherence develop in an untruncated non-Abelian lattice gauge theory.