A researcher of Indian origin at AT&T says that his group has reached one step closer to realising full-fledged quantum computers.

Prem Kumar, Professor of Information Technology in the Department of Electrical Engineering and Computer Science, says that his group has zeroed in on one of the basic building blocks for distributed quantum computing using entangled photons generated in optical fibres.

"Because it is done with fibre and technology that is already globally deployed, we think that it is a significant step in harnessing the power of quantum computers," Kumar says.

Unlike classical computing that works by processing bits, that is, processing results either in one or in zero, quantum computing uses quantum bits (qubits) wherein a 'superposition' or simultaneous existence of one and zero is possible.

The "superposition" state allows a quantum computer to process significantly more information than a classical computer in a much shorter time.

Researchers say that achieving this state is possible because qubits are quantum units like atoms, ions or photons, which operate under the rules of quantum mechanics instead of classical mechanics.

Kumar’s group used photons as qubits, and found that two indistinguishable photons could be entangled together in an optical fibre by using the fibres inherent non-linear response.

The researchers also noted that no matter how far the two photons were separated in standard transmission fibres, they remained entangled and were "mysteriously" connected to each others quantum state.

For this research, Kumar’s team used the fibre-generated indistinguishable photons to implement the most basic quantum computer task a controlled-NOT gate, which allows two photonic qubits to interact.

"This device that we demonstrated in the lab is a two-qubit device, nowhere near whats needed for a quantum computer, so what can you do with it? Its nice to demonstrate something useful to give a boost to the field, and there are some problems at hand that can be solved right now using what we have," Kumar says

A research paper describing Kumars study has been published in the journal, Physical Review Letters.

ANI