DMRG study of spin-imbalanced fermionic cold atoms trapped on optical ladders --- evolution of spin-aligned domains

DMRG is used to study spin-imbalanced fermionic cold atoms that reside on a two-leg optical ladder and trapped to a finite region to explore the spin structure. We find that the ground state comprises phase-separated regions that include fully spin-polarized, partially polarized, and non-polarized domains for strong on-site repulsions. We determine the conditions for realizing large itinerant ferromagnetic (fully polarized metallic) regions.