We explore how the initial conditions affect the final lepton asymmetry in
Soft Leptogenesis. It has been usually assumed that the initial state is a
statistical mixture of sterile sneutrinos and anti-sneutrinos with equal
abundances. We calculate the lepton asymmetry due to the most general initial
mixture. The usually assumed equal mixture produces a small, but sufficient,
lepton asymmetry which is proportional to the ratio of the supersymmetry
breaking scale over the Majorana scale. A more generic mixture, still with
equal contents of sneutrinos and anti sneutrinos, yields an unsuppressed lepton
asymmetry. Mixtures of non equal contents of sneutrinos and anti sneutrinos
result in a large lepton asymmetry too. While these results establish the
robustness of Soft Leptogenesis and other mixing based mechanisms, they also
expose their lack of predictive power.Comment: v1: 12 pages; v2: typos corrected; v3: published version with new
discussions and reference
