yet you think it isn ' t real enough to be used in practice ? QM is very real and very well understood . The reason is that nature abhors qubits . Everything in the world around you , including you , is the result of quantum decoherencethe act of qubits collapsingwhich is exactly what you do not want in a QC , since the whole point is to exploit entanglement . It ' s like trying to balance a few dozen needles on their tip in a randomly moving car . While the structure of the universe is literally coming into existing via QMit is doing this via the very process that QC is trying get rid of . Hence , it ' s one of the hardest engineering tasks one could dream up because it is literally fighting a fundamental process of the universe . While some think its a genius idea , others think its a pipedream . There are good arguments for both sides .