I don't think it even requires "extended professional training". A healthy dog, not bored and in a proper environment has no reason to bark all day.
Dogs can be trained not to bark in (inappropriate) response to stimuli that are new to them, stressful and building up their anxiety.
When you're away from your home you're not able to reward "not barking". So punishment based methods could work (electric collars or the like), as they are able to punish the dog right at the moment of the inappropriate behaviour. I am NOT promoting the use of these devices, just using it as an example: there is no device that "electrically" rewards not barking. Punishment based training is detrimental to the relationship you'll have with your dog and is not a recommended training method (ref. to be added), so if you're thinking about that even before having the dog, I'd think twice.
So that means you need to build calmness into your dog, prevent separation anxiety, and provide him with enough stimulation (toys, food toys, music?) when you're away.
The "calmness" training is done beforehand (I'll try to link to another question/answer about that).
As a summary of the situation, based on my dog:
Inappropriate barking to specific stimuli: this is a training problem, he still have to learn what is an appropriate reaction to certain stimuli. You have to train an alternative, appropriate response (the dog sees a bike, he sits instead of barking) and also build calmness
Inappropriate barking (over-excitement: when he wants to play with other dogs (he doesn't always bark but still...), excitement when going to the vet, etc. That's about building calmness. The sooner you start the better
Appropriate barking: he sometimes starts barking if, when left alone, he sees a bug, fly, etc. I wouldn't call that inappropriate, he is trying to deal with the situation, thank him for his intervention and that's it.
That might not seem like a real answer to your question but it tries to give you some perspective; my point is don't think of it with a "beagle barks" => "training" => "problem solved" approach.