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September 27, 2006

Adjustable 'ion trap' helps find best trap size and temperature for quantum computing

The first adjustable "ion trap" help to understand how the size of the ion trap and temperature effect quantum computing effects.

Conventional ion traps confine atomic particles within a vacuum and an electric field generated by two fixed-position electrodes. The electronic states of these particles can be used to represent quantum bits of information. Unlike normal "bits" of information, which are represented by distinguishable states, such as a binary "1" or a "0", quantum information can exist in different states simultaneously
The new trap allows the distance between each electrode to be adjusted without losing the ion trapped in-between.

For the first time, this allowed them to measure precisely how down-scaling the trap affected the quantum state of the trapped ion. They found that reducing the size of the trap increased its temperature, thus boosting "decoherence", which could ultimately destroy quantum information.

It was still possible to shrink the trap down to 23 microns in diameter – the smallest ion trap ever made – without impairing its function. And, by cooling it to -120°C, they were able to reduce the heating that threatened to destroy to the ion's quantum properties.

Hensinger estimates that it should be possible to scale down an ion trap even further, to around 1 micron, providing it is cooled sufficiently. This could prove crucial as a practical quantum computer would require hundreds of thousands of such devices in order to perform useful calculations.



Other reading:
Ion traps could scale to thousands of qubits

Quantum computer summary

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