Traditional transistor-based computers process information by reading combinations of “1” and “0”. According to Moore’s Law, the number of transistors that fit on the current style of microprocessor doubles roughly every 18 months. The computers of the early 21st century are light years ahead of the first models created some 50 years ago, in both speed and portability. Making the move to using qubits will not only improve on that speed, but change the way that computers process information.
Qubits are quantum bits of information encoded at an atomic level. Control devices are used to manipulate the microscopic qubits in a quantum computer, allowing them to act as both a processor and a computer memory simultaneously. Examples include the use of magnetic and/or optical fields to create ion traps and the use of light waves to create optical traps. This versatility and ability to maneuver particles on a subatomic level allows quantum computers to be millions of times faster than even the supercomputers of today.
Advances in Creating Single-Atom Transistors
The American and Australian scientists’ recent step towards quantum nanocomputers involved creating a controllable transistor using one phosphorus atom placed on a silicon chip. The atom sits in a channel in order to keep its electrons contained. Scientists used a scanning tunneling microscope to position the phosphorus atom. The microscope scratched out a trench and small hole on the silicon chip, already covered with hydrogen atoms. Then phosphine gas deposited the atom in the tiny hole. The phosphorous atom was then covered with more silicon atoms.
At present the new transistor only functions at very low temperatures of at least -391 degrees Fahrenheit or -196 Celsius, the same temperature as liquid nitrogen. Anything warmer and the electrons move out of the channel and the atom stops functioning as a metal. More work must be done to create a way to contain the electrons at higher temperatures so that this technology may be used at room temperature.
Single-atom transistors were first conceived in 2002. What makes this latest achievement by the Purdue and New South Wales team different is the means of construction. This transistor was engineered successfully with atomic precision. The scientists even created markers so that researchers can apply a power source and conduct further experiments.
What Does This Mean For Computers of the Future?
There is debate among some engineers and scientists as to how small, therefore how fast, conventional computers can be made, or if quantum computers will be a viable future option. Already the answer to “How small is too small?” is changing. The same researchers from Purdue and New South Wales published a report this past January noting that they were able to craft silicon nanowires four atoms wide and one atom tall. These wires were made by using thin strands of the same type of phosphorous atoms used in the transistor. Combining this wire along with the single-atom transistor gives scientists the basic building blocks for the nanocomputers of the future.