What is it, and how does it work? A quantum particle, such as an electron or atomic nucleus, can exist in two states at the same time say, with its spin in the up and down states. This constitutes a quantum bit, or qubit. When the spin is up, the atom can be read as a 1, and the spin down can be read as a 0. This corresponds with the digital 1s and 0s that make up the language of traditional computers. The spin of an atom up or down is the same as turning a transistor on and off, both represent data in terms of 1s and 0s.
Qubits differ from traditional digital computer bits, however, because an atom or nucleus can be in a state of "superposition," representing simultaneously both 0 and 1 and everything in between. Moreover, without interference from the external environment, the spins can be "entangled" in such a way that effectively wires together a quantum computer's qubits. Two entangled atoms act in concert with each other when one is in the up position, the other is guaranteed to be in the down position.
The combination of superposition and entanglement permit a quantum computer to have enormous power, allowing it to perform calculations in a massively parallel, non-linear manner, exponentially faster than a conventional computer. For certain types of calculations such as complex algorithms for cryptography or searching a quantum computer can perform billions of calculations in a single step. So, instead of solving the problem by adding all the numbers in order, a quantum computer would add all the numbers at the same time.
To input and read the data in a quantum computer, a team of scientists uses a
nuclear magnetic resonance machine, which uses a giant magnet and is similar to
the medical devices commonly used to image human soft tissues. A tiny test-tube
filled with the special molecule is placed inside the machine and the scientists
use radio-frequency pulses as software to alter atomic spins in the particular
way that enables the nuclei to perform calculations.