Abelian dominance in local unitary gauges and without gauge-fixing in pure SU(2) QCD

We perform lattice Monte-Carlo simulations of pure SU(2) QCD using the multi-level method. We find Abelian dominance in local unitary gauges such as those diagonalizing a plaquette. A static potential described by Abelian link fields alone gives us the same string tension as that of a non-Abelian potential. Abelian dominance of the string tension and Abelian flux tube profiles are observed also without gauge-fixing, i.e., without any Abelian projection. On the basis of these results, we propose a simple gauge-independent Abelian confinement scenario without any Abelian projection. All color components of the non-Abelian field strength become Abelian dominant in the infrared region. The Abelian dual Meissner effect works in any color direction. Abelian neutral states in any color directions which are just non-Abelian color-singlet can exist as a physical state. In this way, the non-Abelian color confinement could be understood in the framework of the Abelian dual Meissner effect.