Vod is right. There are quantum computers built but they are still primitive to what we can expect. I think the article you pointed out is referring to only D-wave and their claims.
Yea but they only did that in small scale. They can do perfect research in small scale, but can it scale to large ones?
In small scale those experiments are harmless, but if they can scale it, then we are all fucked, as humanity.
So far to my knowledge and understanding of physics, it's impossible to scale the quantum system, because it requires 0 energy or close to 0 energy vacuum to maintain the quantum state, as soon as you introduce energy, the qstate collapses. However you cannot perform operations without energy and manipulating the particles, so it's a paradox in my opinion.
What do you think?