What does this equation mean?

Line up every platform where this cone speed has actually been measured, under one fixed convention — the cone-front group velocity at the relevant filling or interaction strength — and the span comes out to nine and a half orders of magnitude, not the round eleven a first pass at the argument reached for. The bottom of the range is Cheneau’s Bose-Hubbard cone, at 1.1 millimetres per second; the top is graphene’s Dirac cone, whose Fermi velocity runs from about 1$\times$10^{6} metres per second at ordinary carrier density up to roughly 3$\times$10^{6} metres per second near the point where the conduction and valence bands touch, boosted there by weakly screened electron-electron interactions [ 7 , 8 ] . Divide the two and the ratio is 10^{9.44} , not 10^{11} : still a span of nearly ten orders of magnitude, but an honest one rather than the rounder number a tidier story would have preferred.