Example of a silicon quantum chip next to a 20 pence coin.

 

Scientists
from the University of Bristol’s Centre for Quantum Photonics have
developed a silicon chip that will pave the way to the mass-manufacture
of miniature quantum chips. The announcement was made at the launch of
the 2012 British Science Festival (Sept. 4-9, 2012).

The
leap from using glass-based circuits to silicon-based circuits is
significant because fabricating quantum circuits in silicon has the
major advantage of being compatible with modern microelectronics.
Ultimately this technology could be integrated with conventional
microelectronic circuits, and could one day allow the development of
hybrid conventional / quantum microprocessors.

The
Bristol-led team have developed quantum chips from silicon—the same
material routinely used en masse to build the tiny electrical processors
in all computers and smart phones. However, unlike conventional silicon
chips that work by controlling electrical current, these circuits
manipulate single particles of light (photons) to perform calculations.
These circuits exploit strange quantum mechanical effects such as
superposition (the ability for a particle to be in two places at once)
and entanglement (strong correlations between particles that would be
nonsensical in our everyday world). The technology developed uses the
same manufacturing techniques as conventional microelectronics, and
could be economically scaled for mass-manufacture. These new circuits
are compatible with existing optical fibre infrastructure and are ready
to be deployed directly with the internet.

Mark
Thompson, Deputy Director of the Centre for Quantum Photonics in the
University’s Schools of Physics and Electrical & Electronic
Engineering, said: “Using silicon to manipulate light, we have made
circuits over 1,000 times smaller than current glass-based technologies.
It will be possible to mass-produce this kind of chip using standard
microelectronic techniques, and the much smaller size means it can be
incorporated in to technology and devices that would not previously have
been compatible with glass chips.

PhD student Erman Engin measuring the performance of a silicon quantum chip.

“This
is very much the start of a new field of quantum-engineering, where
state-of-the-art micro-chip manufacturing techniques are used to develop
new quantum technologies and will eventually realise quantum computers
that will help us understand the most complex scientific problems.”

Along
with recent demonstrations from the Bristol research group and other
groups showing on-chip generation of photonics qubits and results from
the US showing on-chip detection of single photons, the Bristol-lead
research team now believes that all the key components are in place to
realize a fully functioning quantum processor—a powerful type of
computer that uses quantum bits (qubits) rather than the conventional
bits used in today’s computers. Quantum computers will have
unprecedented computational power for tasks including search engines and
the design of new materials and pharmaceuticals. This work, carried out
with collaborators including Heriot-Watt University in Scotland and
Delft University in the Netherlands, is an essential step towards the
miniaturizations of quantum technologies.

Source: University of Bristol