TITLE: Can the field of Laurent series be made into an Archimedean ordered field?
QUESTION [5 upvotes]: In today's analysis class, my professor introduced the field of formal Laurent series $\Bbb R((x))$. He also talked about the dictionary order on $\Bbb R((x))$ and why it is not an Archimedean ordered field. One natural question arises:

Can $\Bbb R((x))$ be made into an Archimedean ordered field?

My professor answered that there are uncountably orders on $\Bbb R((x))$, but none that he knows of make it an Archimedean field. Since we know that every Archimedean field can be embedded into the real number and conversely, every subfield of $\Bbb R$ is Archimedean, the question transforms into:

Can $\Bbb R((x))$ (as a field) be embedded into $\Bbb R$?

The new formulation doesn't seem easier, but it makes the problem a purely algebraic one.

Thanks for nombre's answer, $\Bbb R((x))$ cannot be embedded into $\Bbb R$ for the simple reason that it contains a copy of $\Bbb R$. Now I wonder if $\Bbb Q((x))$ embeds into $\Bbb R$.

REPLY [3 votes]: There is no embedding
$f:\Bbb{Q}[[x]]\to \Bbb{R}$ neither: take $n\in \Bbb{Z}$ such that $f(1+nx)=1+nf(x)< 0$ then $f((1+nx)^{1/2})$ is purely imaginary.