Researchers at the University of Oxford have built a scalable quantum supercomputer capable of quantum teleportation – a huge milestone in quantum computing. They claim that it will allow the creation of “next-generation technology” distributed at an industry level.
The researchers hope that this technique of quantum teleportation could facilitate a future ‘quantum internet’ which would create an ultra-secure network for communications and computation. It has the possibility of massively improving Artificial Intelligence capabilities, optimise logistical and financial models, and improve drug discovery techniques.
The breakthrough comes from addressing the ‘scalability problem’ in quantum physics, which is the difficulty of constructing a large, reliable quantum computers without excessive errors. A qubit is a unit of information, similar to a binary ‘0’ or ‘1’ in a regular computer, but it can be both simultaneously, known as ‘superposition’. As more qubits are added, maintaining their stability and preventing interference becomes increasingly difficult, limiting practical applications.
The new method developed links small quantum devices together which enables computations to be distributed across the network so there is no limit to the amount of processors that could be in the network and they take up less space.
Dougal Main, study lead from the Department of Physics, said that “previous demonstrations of quantum teleportation have focussed on transferring quantum states between physically separated systems.” This study, he continues, uses quantum teleportation to create interactions between these distant systems. “By carefully tailoring these interactions, we can perform logical quantum gates – the fundamental operations of quantum computing – between qubits housed in separate quantum computers.”
The formation is based on molecules which only contain a small number of trapped-ion qubits each. These are linked though optical fibres and light (photons) rather than electrical signals to transmit data between them. The photonic links enable qubits in separate modules to be enabled and quantum logic to be performed across the models. This is, briefly, quantum teleportation.
“Our experiment demonstrates that network-distributed quantum information processing is feasible with current technology,” said Professor David Lucas, lead scientist at the UK Quantum Computing and Simulation Hub and principal investigator of the project’s research team.
“Scaling up quantum computers remains a formidable technical challenge that will likely require new physics insights as well as intensive engineering effort over the coming years.”
The researchers used Grover’s search algorithm to demonstrate the effectiveness of this method. The technique searches for a certain item in a large and unstructured database much faster than a regular computer can. This is achieved using quantum phenomena of superposition and entanglement to explore many possibilities in parallel. Its successful demonstration shows how a distributed approach can extend quantum capabilities beyond the limits of a singular device, facilitating the development for scalable, high-performance quantum computers. The new quantum computers will be powerful enough to run calculations in hours that today’s supercomputers would take many years to solve.
The findings were published in the journal Nature, in a study titled ‘Distributed quantum computing across an optical network link’.
