Special museum visiting hours for academics?
Generally no, there is no time set aside for academics only in nearly all museums. Academics are members of the public like anyone else and are invited in when the museums are open. With advanced notice, researchers may be allowed to view some items in the museum collection that are not on display (depending on a lot of factors), but for items on display you are expected to access the galleries like anyone else. 

All that said, many academics who work seriously on museum material and move in museum circles often are invited to visit museums at non-opening times (e.g. On a Monday when the building is closed to the public but staff are working). Usually if you are let in at this time it is for a clear purpose, such as working with or visiting a curator, and you aren't left to wander about on your own as that's a huge security risk. I've been in many museums before opening, after closing, or on closed days, for various reasons (projects, personal tours given by friends who work there, filming, etc). "Because the public is noisy" has not been one of those reasons. I do my gallery observation work during regular opening hours with everyone else. 

For the Louvre, go on their weekday late night opening. There are surprisingly few people there at that time and the lighting is magical.