Flavor Asymmetry of Nucleon Sea from Detailed Balance
  In this study, the proton is taken as an ensemble of quark-gluon Fock states. Using the principle of detailed balance, we find $\bar{d}-\bar{u} \approx 0.124$, which is in surprisingly agreement with the experimental observation. 
Yong-Jun Zhang, Bo-Qiang Ma, Li-Ming Yang