Bristol Centre for Quantum Photonics develops a silicon chip
Scientists from Bristol’s Centre for Quantum Photonics have developed a silicon chip that could be used to perform complex calculations and simulations using quantum particles in the near future. The researchers believe that their device represents a new route to a quantum computer – a powerful type of computer that uses quantum bits (qubits) rather than the conventional bits used in today’s computers.
“It is widely believed that a quantum computer will not become a reality for at least another 25 years,” says Professor Jeremy O’Brien, Director of the Centre for Quantum Photonics.
“However, we believe, using our new technique, a quantum computer could, in less than ten years, be performing calculations that are outside the capabilities of conventional computers.”
The technique developed in Bristol with researchers from Tohoku University, Japan, the Weizmann Institute in Israel and the University of Twente in the Netherlands uses two photons moving along a network of circuits in a silicon chip to perform a quantum walk.
This has been done before with one photon and can be modelled exactly by classical wave physics. However, this is the first time a quantum walk has been performed with two particles. The paper is published today in Science.
“Using a two-photon system, we can perform calculations that are exponentially more complex than before,” said O’Brien.
“This is very much the beginning of a new field in quantum information science and will pave the way to quantum computers that will help us understand the most complex scientific problems.”
In the short term, the team expect to apply their new results immediately for developing new simulation tools in their own lab. In the longer term, a quantum computer based on a multi-photon quantum walk could be used to simulate processes which themselves are governed by quantum mechanics, such as superconductivity and photosynthesis.
“Our technique could improve our understanding of such important processes and help, for example, in the development of more efficient solar cells,” said O’Brien.
“Now that we can directly realize and observe two-photon quantum walks, the move to a three-photon, or multi-photon, device is relatively straightforward, but the results will be just as exciting. Each time we add a photon, the complexity of the problem we are able to solve increases exponentially, so if a one-photon quantum walk has 10 outcomes, a two-photon system can give 100 outcomes and a three-photon system 1000 solutions and so on.”
See www.bristol.ac.uk for more info.