What is a $\mathbb{Q}$-automorphisms of $\mathbb{R}$ ? Does this mean, I have to think if $\mathbb{R}$ as a $\mathbb{Q}$ vector space ? Or does that mean, that it is an automorphism on $\mathbb{R}$ that restricted to $\mathbb{Q}$ is the identity (this was some definition I picked up on the web, searching for an explanation)?
And can someone please tell me how I could find all of these automorphisms ?