Generally no the police cannot break down your door to enter. Oftentimes they do, as unfortunately we've seen it, and I've seen it with many clients. What the police are supposed to do is do what's called a knock and announce. They're supposed to knock on your door. They're supposed to announce that they're the police, that they're there, and they have a warrant to search the home.
Oftentimes they'll do this within a split second of knocking down the door because they think people are inside destroying evidence. It's very important to talk to your attorney about this, and there could be a possible motion to suppress based on this illegal activity by the police.