According to German website GameStar, the PC version of Quantum Break will be released alongside the Xbox One release on April 5th. The website claims to have received news of the PC version of the game straight from Remedy during a preview event.
The article from GameStar has now been removed, but few minutes later it was officially confirmed.
Quantum Break is indeed coming to PC. The game will be released as rumored on April 5th, together with the Xbox One release. An Xbox One Bundle including the game has also been confirmed.