The sense this term is using 'quantum' is as a shorthand for a point in time, where attacking cryptosystems using quantum computers becomes feasible. So you ca

The sense this term is using 'quantum' is as a shorthand for a point in time, where attacking cryptosystems using quantum computers becomes feasible. So you can talk ante-quantum and post-quantum in this sense, but it makes little sense to talk about just 'quantum', in exactly the same way that we schedule a lot of things AM and PM but very little for precisely noon.