Fulde-Ferrell-Larkin-Ovchinnikov critical polarization in   one-dimensional fermionic optical lattices
  We deduce an expression for the critical polarization P_C below which the FFLO-state emerges in one-dimensional lattices with spin-imbalanced populations. We provide and explore the phase diagram of unconfined chains as a function of polarization, interaction and particle density. For harmonically confined systems we supply a quantitative mapping which allows to apply our phase diagram also for confined chains. We find analytically, and confirm numerically, that the upper bound for the critical polarization is universal: P_C^{max}=1/3 for any density, interaction and confinement strength. 
Vivian V. Fran\c{c}a, Dominik H\"ordlein and Andreas Buchleitner
cond-mat.supr-con astro-ph.HE cond-mat.quant-gas cond-mat.str-el quant-ph