In other words, your browser is not W3C compliant with respect to URL rendering and will instead show the PUNYCODE equivalent rather than the multilingual Unicode characters as it should. As a result, your browser was directed to this page, which shows the standard ASCII square-root-domain.com instead of √.com. You see, PUNYCODE was never intended by the IDNS WG to be seen by the end-user but some browsers just haven't caught up with the current technology.
If you want to see this URL properly, then do one of the following: If you're running Windows: There are plug-ins that will allow IE to support IDNS here.
Then switch to the Safari Browser.