Affiliation: Indian Institute of Technology, Bhubaneswar

Low-lying hadrons in the matrix model of two-color QCD at extreme stong coupling:
quantum phases and the spin-puzzle

2-color QCD (SU(2) gauge theory coupled to fundamental fermions) has several novel features: for instance, enhanced Pauli-Gursey symmetry yields degeneracies between mesons and di/tetra-quark states. The quantum mechanical matrix model provides a simplified platform to directly probe the properties of low-energy (spin-0 and spin-1) hadrons. Using variational calculation, we numerically obtain the energy eigenstates and eigenvalues of the matrix model at ultra-strong coupling. In chiral limit, the effects of non-perturbative axial anomaly are quantified. Interestingly, in chiral limit, gluons contribute significantly (almost 50%) to spin of hadrons and spin-0 hadrons are primarily composed of reducible connections. These effects are suppressed in heavy quark limit. Further, at strongly coupling, the system can undergo quantum phase transitions (in presence or absence of chemical potential). The ground state can be a spin-1 di-quark state which spontaneously breaks spatial rotational symmetry.