Quantum Computing is a radically new approach to computing. For this, you have to work in very cold temperatures. Quantum information is very fragile, so besides very low temperatures you also need darkness. Noise has to be avoided, too, so the technology behind it is very complex.
The idea behind it is much older, but it needed some time before it could be realized. The molecule of caffeine, for example, is much less complicated than for example DNA. But writing down this information would need many bits, 10 to the power of 48 classical bits – until today this molecule can not calculate it exactly. But Quantum can do it, in 160 Quantum bits.