Quantum Computers :: quantum physics computer

miss figuresWith todays engineering science we are able to squeeze millions of micron wide logical system gates and wires onto the surface of silicon chips. It is only a topic of magazine until we come to a point at which the gates themselves will be made up of a mere handful of atoms. At this scale, matter obeys the rules of quantum mechanics. If computers are to become smaller and more powerful in the future, quantum technology must replace or reinforce what we have today. Quantum computers arent limited by the binary nature of the classical physical world. Instead, they depend upon observing the convey of qubits (quantum bits) that may represent a one or a zero, a combination of the two, or that the state of the qubit is somewhere between 1 and 0. This intermix of states is known as superposition.Here a light source emits a photon along a path towards a half-silvered mirror. This mirror splits the light, reflecting half vertically toward demodulator A and transmiting sic half toward detector B. A photon, however, is a item-by-item quantized packet of light and send wordnot be split, so it is detected with commensurate fortune at either A or B. Intuition would swan that the photon randomly leaves the mirror in either the vertical or crosswise direction. However, quantum mechanics predicts that the photon actually travels both paths simultaneously ... This effect, known as single-particle disturbance, can be better illustrated in a slightly more thrive experiment, outlined in figure b below1In this experiment, the photon first encounters a half-silvered mirror, then a fully silvered mirror, and finally some other half-silvered mirror before reaching a detector, where each half-silvered mirror introduces the probability of the photon traveling down one path or the other. Once a photon strikes the mirror along either of the two paths after the first shine splitter, the arrangement is identical to that in figure a, and so one cogency hypothesize that the photon will reach either detector A or detector B with equal probability. However, experiment shows that in reality this arrangement causes detector A to register 100% of the time, and never at detector B2This is known as quantum interference and results from the superposition of the come-at-able photon states, or potential paths. So although only a single photon is emitted, it appears as though an identical photon exists and travels the path not taken, only detectable by the interference it causes with the original photon when their paths come together again.