Imperfect Omni-directional Engine Framework

A two-stage kinetic sieve mechanism is proposed to explain the cosmological Lithium Problem — the factor of 2.985× deficit between the Big Bang Nucleosynthesis prediction (PRIMAT v0.3.0: A(Li) = 2.674) and the observed Spite Plateau (GALAH DR3: A(Li) = 2.199). Stage I (Ballistic Fractionation) derives a 2.09× depletion from charge-dependent drag coefficients using the Saha equation — no free parameters. Stage II (Neutral-Gap Drag) derives a 1.44× depletion from Stokes drag on ionized Lithium during the window between Hydrogen neutralization (3,700 K) and Lithium neutralization (1,200 K). Combined baseline: 3.01×, matching the required 2.985× within 0.8% of input rounding. The mechanism predicts a density-dependent gradient: lower-density environments produce greater depletion, consistent with the factor-of-4 Lithium deficit observed in the Small Magellanic Cloud ISM (Howk et al. 2012) after applying maximum dust corrections (Roman-Duval et al. 2021). The primary falsification test — cross-matching metal-poor halo star Lithium abundances against cosmic web environment classifications — is executable against existing public data.