Japanese Researchers Transport Quantum Information Within a Diamond

Researchers at Japan’s Yokohama National University have successfully transported quantum information within a diamond.

This recent breakthrough has significant implications in the future of how sensitive information can be stored and shared securely.

Prof. Hideo Kosaka, a professor of engineering at the Yokohama National University and a co-author of the study, said:

“Quantum teleportation permits the transfer of quantum information into an otherwise inaccessible space. It also permits the transfer of information into a quantum memory without revealing or destroying the stored quantum information.”

Quantum teleportation will allow the development of quantum communication systems capable of transmitting sensitive information securely between two points, regardless of the distance.

Back in August 2017, a quantum experiment conducted by Chinese researchers saw a photon successfully transported between two ground stations that were over 1,200 km apart.

With Prof. Kosaka and his team’s experiment, they aimed to transmit data in a place where it doesn’t usually go.

Transporting Quantum Information

In their paper published in the journal Nature Communications Physics, the researchers described using the “inaccessible space” within the diamond as the destination of their quantum data.

Diamonds are made up of carbon atoms that hold six protons and six neutrons each in their nucleus. These carbon atoms bind together to form a sturdy lattice.

However, when a nitrogen atom gets in between two adjacent empty spaces where carbon atoms should be placed, it causes a defect on the diamond.

Scientists call this defect as the nitrogen-vacancy center. Prof. Kosaka further explained that the nitrogen atom’s nucleus creates a nanomagnet within the diamond.

Quantum Information teleportation — The lattice structure of diamond contains a nitrogen-vacancy center with surrounding carbons. A carbon isotope (green) is first entangled with an electron (blue) in the vacancy, which then waits for a photon (red) to absorb, resulting in quantum teleportation-based state transfer of the photon into the carbon memory. | Image courtesy of Yokohama National University

The Japanese scientists attached a nanowire to the surface of the diamond to manipulate the carbon isotope and electron within the diamond’s nitrogen-vacancy center.

Microwave and radio waves were applied to the wire, whose size was about a quarter the width of a human hair, to form an oscillating magnetic field around the diamond.

Then, Prof. Kosaka and his team shaped the microwave to generate the perfect, controlled conditions for the transportation of the quantum information within the confines of the diamond.

Using the nanomagnet, together with the microwave and radio waves, the scientists entangled the electron spin with the carbon nuclear spin.

Once the electron and carbon nuclear spins entered the state of entanglement, it absorbed the quantum information-containing photon applied by the researchers.

The absorption enabled the photon’s polarization state to transfer the information into the carbon through the entangled electron, completing the transportation process at a quantum level successfully.

Prof. Kosaka noted:

“The success of the photon storage in the other node establishes the entanglement between two adjacent nodes. Our ultimate goal is to realize scalable quantum repeaters for long-haul quantum communications and distributed quantum computers for large-scale quantum computation and metrology.”