A new experiment out of the University of Southern California might have solved one of the toughest problems in quantum computing, and it did so by building a computer inside a diamond... Researchers used a neutron as one qubit, and an electron as the other. This mismatched pair was used in order to accurately measure the level of decoherence. An electron, being smaller, is capable of faster calculations, but suffers more from decoherence. Neutrons are slower, but much more stable. In the experiment, scientists found that a series of microwave pulses hitting the diamond computer “reset” the particles and reduced data loss through decoherence. At this point, there is no practical application for a simple quantum computer, and no real world test to show it working. The team at USC was able to prove that they had indeed built a solid-state quantum computer by supplying it with a simple data set, and applying Grover’s algorithm, which is a mathematical proof demonstrating the potential power of quantum computers. Grover’s algorithm states that a quantum computer will be able to find a specified entry in an unsorted list on the first try, every time. A human trying to do this would have to go down the list checking each entry to see if it was the right one. Going this route, you would on average check half the list before finding the right entry. This diamond-encrusted computer was able to find the correct choice on the first try 95% of the time, thus proving that the researchers successfully built a functional quantum computer. http://news.usc.edu/#!/article/27023/quantum-computer-built-inside-a-diamond Still, it's a big step towards the sort of computers we'll be using in the future M