Wetenschappers van de Purdue University zijn er in geslaagd om quantum computers met behulp van quantum dots een stapje dichterbij te brengen. Een quantum computer is in tegenstelling tot een normale computer niet opgebouwd uit bits, maar uit qubits. Een soort van bit die tegelijkertijd de waarde 0 en 1 kan bezitten. Deze qubits kunnen opgebouwd worden uit quantum dots, kleine groepjes elektronen. Om hiermee te kunnen rekenen is het nodig om informatie van de ene qubit naar de andere qubit te transporteren. En dat is wat de onderzoekers gelukt is:
When quantum dots contain only one electron in their outermost level, their spins can be detected by analyzing the flow of electricity through the dots, Chang said.
The researchers were able to achieve the milestone by creating extremely fine circuits using a standard process known as electron beam lithography. A semiconducting material known as gallium arsenide was coated with a plastic. Then extremely fine lines were cut into the plastic coating using a beam of electrons. The lines were filled with a metal and the plastic dissolved, leaving behind metal lines that are like wires only about 50 nanometers wide. A nanometer – or billionth of a meter – is roughly five to 10 atoms wide.
"As far as we know, no other groups have been able to do such fine lithography," Chang said.
Other researchers have already built quantum computing devices based on man-made molecules containing fluorine atoms. However, many experts believe it will be difficult to "scale up" such devices to make large, workable computers.
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