MrSeb writes: "A new experiment out of the University of Southern California (USC) might have solved one of the toughest problems in quantum computing, and it did so by building a computer inside a diamond. This new computer isn’t going to be doing your taxes any time soon, but it shows the viability of solid-state quantum computers to lessen decoherence. Put simply, decoherence is a loss of observable information, which is the last thing you want in a computer. The diamond computer developed at USC makes use of the impurities in the crystalline structure to make up its two quantum bits, or qubits. The researchers were 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. USC's 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."