Ideally, $\alpha$ should be bounded by a polynomial in $\frac 1 \epsilon$.
I feel like intuitively, this is obvious, because the logarithm grows much slower than the identity function. However, I fail to find an actual function $\alpha$ that works for all values of $\epsilon$.
(The reason I'm asking this question is because I'm trying to prove a (fully-polynomial) approximation scheme.)
Here's an answer to your question, but don't think it'll be useful for approximation (in which case you may need to edit your question to add additional properties to $\alpha(\epsilon)$). $$\alpha(\epsilon) = \epsilon + 1$$
$\alpha(\epsilon)$ is bound by polynomial $p(\frac{1}{\epsilon}) = .17$ and $\frac{\log \left(\epsilon+1\right)}{\epsilon+1} < \epsilon$ for all $\epsilon > 0$