Single atom in an ion trap, by David Nadlinger
Building a quantum computer using individual atoms

How can you control individual atoms so that they can be used as the building blocks of a quantum computer?

We are aiming to build a quantum computer using ion traps as qubits, the ‘quantum bits’ within our machine. An ion is an electrically-charged atom, where an outer electron has been stripped away, leaving the whole atom with an electric charge. An ion trap is a device which controls individual ions by making them levitate stably within an electric field. Once trapped, they can be controlled with lasers and used for information processing in our quantum computer.

Ion traps are really small, but we can build them on to a microchip, similar to what you have in your home computer. These are then put inside a vacuum, so no other atoms can get in the way.

Two energy levels of each ion are selected to represent the ‘0’ and ‘1’ qubit states and these can then be put in a quantum superposition, where the result can be either a ‘0’ or ‘1’ at the same time – this is the real power of a quantum computer that makes it completely different from a regular computer. 

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Image: Single atom in an ion trap, by David Nadlinger