We address the quantitative uniqueness properties of the solutions of the
parabolic equation $
\partial_t u - \Delta u
= w_j (x,t) \partial_j u
- v(x,t) u wherevandwarebounded.Weprovethatforsolutionsu$,
the order of vanishing is bounded by $C(\Vert v\Vert_{L^\infty}^{2/3}+\Vert
w\Vert_{L^\infty}^2)$ matching the upper bound previously established in the
elliptic case. in the elliptic case.