New Record for Qubit Lifetime Over 100 Times Previous

Category: Science & Technology
Posted: June 11, 2012 06:03AM
Author: Guest_Jim_*

Quantum physics is finicky. The act of observing something can cause a system to change and even collapse. This makes it difficult for many quantum mechanical states to live long, but difficult is not the same as impossible. Researchers at Simon Fraser University, Oxford University, and Berlin have successfully made a quantum bit, or qubit, that lasted 192 seconds. The previous record for a similar qubit was 1.75 seconds, and was set by the same team four years ago.

Qubits are the analogy to electronic bits in quantum computers. They store and transfer information but utilize superposition to store multiple states at the same time, unlike conventional bits which only have one state at a time; 0 or 1. Observing a particle in a superposition causes it to collapse to a single state though, so qubits have to be handled very carefully. In this case phosphorus atoms were held within an ultra-pure piece of silicon-28. Silicon-28 is not magnetic, so it will not disrupt the phosphorus qubits. The qubits were put into their superposition with an exact radio-frequency pulse and then kept in their superposition for the 192 seconds with additional pulses, to prevent the phosphorus atoms from interacting with the silicon.

This could be a major step towards a quantum computer because this record was achieved with atoms contained in another material. Qubits have survived over three minutes before, but were in vacuums at the time. The fact that the material was silicon is especially promising as this is the current standard for electronics. It may be a while, but this could lead us to hybrid quantum-electronic processors in the future.

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