IEEE Spectrum: In 1994, Peter Shor of MIT developed an algorithm for using a quantum computer to factor large numbers, a necessary step for decrypting data. Seven years later, Isaac Chuang of MIT and his colleagues created the first quantum system that could run Shor's algorithm, although their system could factor only the number 15. Now Chuang's team has developed a five-qubit system that can factor 15 and be scaled up to factor larger numbers. The researchers used a quantum computer prototype called an ion trap, in which a string of ions held in place by an electric field and manipulated by laser pulses serves as the qubits. As long as the trap can hold the ions in place, the number of qubits can be increased.
