Former exterminator here. Carpenter ants do not nest in the ground, they like to nest in wood. They do not eat the wood like termites, but like to nest in it. They will sometimes get their water from wood, but not food. They will eat just about anything, including other ants and their own dead.
Will they 'wake up" if brought in from the cold? Absolutley yes. They will go dormant in the winter, eventually either freezing to death, if in an unsheltered spot, or just die of starvation.If you have a fertile or fertilized queen ant in the wood, you've got the beginnings of a nest. If it's just a bunch of workers or warrior ants, you will have a pain in the posterior (and an angry wife) for a few weeks or months, until you kill them or they die naturally. They generally do not live more than a few months before dieing off.
If you have a queen ready to lay eggs? Brother, you got a problem. I have seen first hand the enormous amount of damage they can do. I recomend baits. You can mix your own out of Boric acid dust and powdered sugar. Just put it in little cups wherever you see the critters. If you have small kids or pets, I would NOT do this. Boric acid can be nasty if you get it in your kids eyes or up your prize hunting dog's schnoz. Bayer makes some really good bait stations with Fipronil as the chemical. Great stuff, used it at my own house after I brought home some carpenter ants with my firewood. Also used to use it alot on customers houses. Can take a little while to work , but will generally wipe out a nest completely in a couple of weeks.
For any of you geeks, I will splain how it works. When an ant finds food, it immediately eats it, and brings it back to the nest, leaving a pheromone trail to follow back to the source. It then brings it back to the nest, horks it up, where it is fed to the queen , young, and other ants. With the Fipronil, it stays in the ants system, and it will sweat it out. Ants constantly brush up against each other, so a poisoned ant will kill up to a dozen others by touch. Then, when it dies, it is eaten by the other ants, killing more. The other ants follow the pheromone trail laid out by the original ant, bringing more bait back to the nest. The food part of the bait is made up of all the favorite foods of your average carpenter ant, so they love to eat the stuff. I had a few bait stations completely emptied overnight at one customers house.
Do not mess around with carpenter ants. They can and will literally eat you out of house and home. Seen it too many times. They can do major damage if left unchecked. If you can afford an exterminator, call one. But you can certainly lick them yourself using either of the methods I said earlier. Another thing with c-ants is they like to find out where termites are living, kick them out, and take over their tunnels. Both insects prefer water damaged wood (easier to dig, and it provides moisture too), so if you have a nest, there is a good chance it is in water damaged wood. So, you might have a water leak somewhere you are not aware of. I discovered quite a few hidden leaky pipes, leaky gutters, roofs, bad chimney flashing, etc. in my time as a slayer of bugs. You might have significant structural damage to your house and not even know it. They can and will nest in pressure treated wood, I even found a nest in a big old cedar tree once. So no wood is immune to carpenter ants, no matter what the guy at the lumber yard says.
Here endeth the lesson.
