Quantum research achieves 10-fold boost in superposition stability
Tue 18 Oct 2016
A team of Australian researchers has developed a qubit offering ten times the stability of existing technologies. The computer scientists claim that the new innovation could significantly increase the reliability of quantum computing calculations.
Qubits, or quantum bits, like standard binary bits can occupy a 0 or 1 value, but can also take a superposition of both states at the same time. The new technology, developed at the University of New South Wales (UNSW), has been named a ‘dressed’ quantum bit as it combines a single atom with an electromagnetic field.
This process allows the qubit to remain in a superposition state for ten times longer than has previously been achieved. The researchers argue that this extra time in superposition could boost the performance stability of quantum computing calculations.
‘We have created a new quantum bit where the spin of a single electron is merged together with a strong electromagnetic field,’ explained research fellow Arne Laucht, of the UNSW School of Electrical Engineering & Telecommunications. ‘This quantum bit is more versatile and more long-lived than the electron alone, and will allow us to build more reliable quantum computers,’ he added.
Previously fragile and short-lived, retaining a state of superposition has been one of the major barriers to the development of quantum computing. The ability to remain in two states simultaneously is the key to scaling and strengthening the technology further.
‘The greatest hurdle in using quantum objects for computing is to preserve their delicate superpositions long enough to allow us to perform useful calculations,’ noted research lead and program manager at the UNSW Centre for Quantum Computation & Communication Technology, Andrea Morello.
By merging a single atom inside a silicon chip, placed within a static electromagnetic field, the research team was able to extend the lifespan of the qubit to 2.4 milliseconds – over in a flash, yet enough time to offer a considerable jump in quantum operations.
In addition to expanding the superposition time-frame, the researchers also stated that the dressed qubit provides greater capacity for manipulation. According to Morello, the qubit can be controlled in a variety of ways which would be impractical with an ‘undressed’ qubit. For example, he suggested that the qubit could be controlled by modulating the frequency of the microwave field, like an FM radio.
Quantum computing is still some way off, with numerous challenges yet to overcome, including stability and miniaturisation. However, when the technology does arrive, the UNSW team is convinced that its breakthrough will work with the standard silicon chips we use in today’s devices.
‘This result gives us a new tool to create a powerful and reliable quantum processor in silicon, using standard fabrication methods as used for everyday computers,’ said Laucht.