Dec 4 2018
A research team from Institut National de la Recherche Scientifique (INRS) has performed computing operations using very complex quantum states—marking a crucial milestone in the progress of quantum computing.
Using a compact optical platform that manipulates the quantum features of light, Professor Roberto Morandotti and his team are a step closer to developing the first powerful photonic quantum computer. In the journal Nature Physics, the INRS scientists report that they have not only produced a particular group of quantum states-d-level cluster states but have employed them to execute unique quantum operations. The demonstrated states display distinct properties that make them more strong and powerful than any other such states showcased till now.
For close to a decade, Professor Roberto Morandotti has been designing an ambitious system piece by piece by creating chips that use light particles (photons) as the data medium. Photons are produced and transformed on these coin-sized chip structures, so that they can be allotted distinctive quantum properties. His team was the first to effectively create high-dimensional (i.e. quDit) optical cluster states, one of the elements that can enable the current quest to harness the power of quantum computing.
Electronic computer systems are nearing the boundary of their capabilities, but still, the demand for higher computing power is continuously growing. This is why researchers are looking at quantum computing, exploring how to encode a substantial amount of information in light particles and undertake calculations of unparalleled complexity.
To reach there, the data medium has to be moved to quantum bits (or qubits), the non-classical computing equivalent of traditional bits. By carefully designing the quantum state of the photons, it is feasible to expand the information storage capacity of qubits and boost them to acquire so-called quDits. Then, by grouping the quDits into clusters, quantum computing processes based on the so-called ‘one-way’ scheme become conceivable.
Other methods to quantum computing use atoms, ions, or other quantum resources, but the efforts to work them towards a higher-dimensional encoding have been unsuccessful. According to Professor José Azaña (INRS), an expert of telecommunications who contributed to this study, photons also offer another benefit: “They are used to transmit information via optical fibers in existing telecommunications systems. That means photons with controlled quantum properties can also travel through these same channels without losing their attributes.”
The richness and complexity of the cluster states described in the article in Nature Physics are extraordinary. Furthermore, researchers also accomplished another first by performing high-dimensional quantum computing tasks harnessing the realized cluster states.
They showed that light has all the essential features to power the superfast computers of the future. In a noteworthy leap forward, this was done with a compact system well-matched with current technologies. The platform put together by the INRS team can produce quantum states with complexities sufficient to attain quantum computing objectives, thereby simplifying the way to one-way quantum computers.