Quantum Computing: Breakthrough by B'luru physicists

A breakthrough in nanotechnology by 10 Bengaluru physicists may open up a new window to look at the creation of quantum computers in the future.

Considered the Holy Grail of computing, quantum computing has been a subject of intense theoretical research for close to four decades.

But so far no one has been able to develop a quantum computer – considered to be way above modern computers – because of several practical difficulties in building such a machine.

The Indian Institute of Science (IISc) team has now demonstrated how at least one of the critical problems in making the futuristic machine can be overcome.

The material they used is called graphene, a thin layer of pure carbon atoms that are arranged in a special hexagonal honeycomb structure with unique properties.

One such wonder property of graphene is its ability to conduct electricity with zero resistance in a particular configuration. The Bangalore scientists figured out how that property could be tweaked so that graphene nano-ribbons can be used as the building blocks for the circuits in a quantum computer.

The graphene ribbons can have a dimension of 5-10 nanometre (one nanometre is one billionth of a metre). The world of the ultra-small exhibit several magical properties, some of which were exploited by the Bengaluru team.

“We have shown how circuits for room-temperature quantum computers can be made. But there are several more challenges that need to be overcome before one can make a machine. We have to improve upon the chemistry and engineering aspects of the research,” team leader Arindam Ghosh told DH. The findings have appeared in Nature Nanotechnology.

“We outline a new resource for one-dimensional quantum transport, which is accessible even at room temperature, opening prospects for room-temperature ballistic quantum circuits, spintronics and quantum information technology,” the team reported in the journal.

In quantum computing, the processors use quantum rules that govern the world of atoms to carry out powerful calculations, whereas in spintronics (spin transport electronics), the spin of an atom is used for computing.

Both are theoretical concepts to create extremely powerful computers that can do several complicated tasks like predicting weather and stock market movements with accuracy and precision – a task beyond the ability of modern computers.

The biggest limiting factor in realising such a machine now is that they cannot operate in room temperature. Success for the IISc scientists came after almost two decades of R&D in laboratories around the world.