In the paper “Coherent spin manipulation of individual atoms on a surface,” published yesterday in the journal Science, team IBM demonstrated the use of single atoms as qubits for quantum information processing.
The credit behind goes to the Noble prize winning IBM’s invention, the Scanning Tunneling Microscope (STM) where the single atom qubit was first seen. STM also allows the atoms to be moved individually, the STM consists of the ultra small needle that scans the surface to sense the arrangement of each and every atom. The needle tip can also carry and place individual atom to desired arrangements
IBM wrote in their blog:
In our experiments, we use a quantum property of a titanium atom called “spin” to represent one qubit. The spin property makes each titanium magnetic, so it behaves like a tiny compass needle. Like a magnet on a refrigerator, each titanium atom has a north and south magnetic pole. The two magnetic orientations define the “0” or “1” of a qubit. We placed the titanium atom on a specially chosen surface, an ultra-thin layer of magnesium oxide, to protect its magnetism and allow it to show off its quantum personality.
By applying high-frequency microwaves, to the titanium atom, quantum superposition state was achieved. These microwaves, steer the atom’s magnetic direction and when the right frequency was produced, these microwaves lead the titanium atom to perform a “quantum dance”. The atom is still on the surface but when a waves are applied, the north of the atom spirals around and this happens in 20 nanoseconds time to turn the qubit from pointing up to “0” and then back down to “1”. This is called the “Rabi Oscillation”. So we could say that by the end of the dance the atom points towards “0” or “1” or the superposition which lies in between the two.
The basic computers that we use have the information in the form of a “bit” and the one that is possessed by the quantum is called a “qubit”. A bit can have any one of the two values i.e either “0” or “1” but the qubit apart from having the above feature also has the ability to stay in between. So we can say that the value is part “0” and part “1” and hence the term SUPERPOSITION STATE.
The qubits are extremely sensitive to magnetic field and hence to accomplish how to rule many qubits at a time is kinda arduous. The possibilities are that we’ll soon find out the answer to it because hey! we’re living the tomorrow already.