It all depends on temperature and ventilation in the room. If you keep heating on and an open window for draft than 3 days would be enough. That does obviously depends on depth of concrete that has been installed, as the higher quantity the longer it needs to cure.
Knowing that its a carpet i would not worry to much, as dampness if there was any coming up would dry out in time. If it was laminate or other covering which doesn't let the floor breath than i would leave that for minimum of two weeks in ambient temperature.
Hope this helps
Mados