Using extremely low temperatures and extremely powerful magnetic fields, a multinational team of university researchers was able to read the quantum state of silicon atoms in a wafer. The team of researchers was also able to increase drastically the time span in which these atoms were stable. John Matson reported on this on November 19, 2008, at sciam.com, in an article titled Quantum Computing Advances a Qubit Closer to Reality.
The conventional processor uses bits, which can be either 0 or 1; the hypothetical quantum processor uses qubits, or quantum bits, which take the form of 0, 1, or both 0 and 1 simultaneously. This would greatly increase computing power.
In temperatures below -270 degrees Celsius (-450 degrees Fahrenheit, 3 Kevin), the researchers implanted a phosphorus atom into a silicon wafer, this adds a “free” electron (because phosphorus has charge 1-) that can be controlled and monitored. The researchers then used “millimeter-wave radiation” to change the spin while they examined the electrical current flowing through the wafer. This method is inaccurate, because it examines the qubits of “a few thousand” electrons, whereas to have a valid processor would have to examine only one electron at a time. This range, the researchers say, will be narrowed, now that the hurdle of reading the state has been passed.
A problem with using phosphorus occurs because the spin could only be maintained in the wafer for about two millionths of a second in previous experiments. A magnetic field 25 times stronger than any used in prior research, along with the cold temperatures, increased this time span 50 fold, making it slightly more feasible for use.
Though scientists are still quite far from reaching a usable quantum computer, this is another advancement toward the “holy grail” of computing.
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