I f the police have an arrest warrant, do they have to know that you are home for sure before they can get the landlord to let them in or can they go in at anytime?

Apparently you haven't been paying attention to the erosion of civil rights under the Bushies. While it's supposed to be for terrorism/nat'l security, police have adopted for all sorts of crimes the snesk & peek - they can enter and search and confiscate w/o even notifying you.

That said, I think even before then they could get the landlord to let them in any time as long as they had a search warrant. If it was an arrest warrant and they knew you weren't there, I'm not sure.