Beyond Asimov

Sending entangled photons over the oceans by containers ships. Credit: Technology Review

Asimov, to me, has always represented the most daring vision of a future that although having some sort of scientific underpinning was basically beyond scientific possibility. However, as time goes by some of Asimov ideas drift into the domain of scientific goals that might be achieved. 
At the same time, the progress of science is generating wild ideas that were too "wild" even for Asimov to imagine. And I feel this is one of those.

Simon Devitt, a researcher at Ochanomizu University in Japan, and his team have come up with the idea of creating a secure Internet by using container ships to transport entangled photons across the oceans.

One technique to ensure immediate detection of an attempted hacking on bits transported over the Internet  takes advantage of an exotic property of quantum mechanics: a pair of photons being tied one another by the entanglement property is used to detect any attempt of tampering with information being transmitted. The entanglement makes sure that if one photon is read by a device the other photon (that is transmitted over a different line) will immediately reverse its status (spin) serving as a red flag. If this seems impossibile given the fact that the relativity principle assures us that no instantaneous communications can exist you are in a good company. That was exactly the point made by Einstein about this phenomena to disprove quantum theory and yet this is what has been shown over and over to be the case. So we have to live with its impossibility and at the same time with its reality.

The photon entanglement is already used to ensure secure communications for data transmission over optical fibre. The problem is that a photon can only travel a few hundred kilometres and then it is absorbed. The solution is to insert optical amplifiers in the fibre that regenerate the photon making possibile signal transmission over thousands of kilometres. However, the regeneration of the photon destroys its entanglement!  There have been studies on how to preserve the entanglement in the regeneration process but the only way found, so far, requires a regeneration near 0 degrees Kelvin and that requires very expensive infrastructures and besides it cannot be done at the bottom of the oceans where transoceanic fibres are used to connect continents.

So now it comes Simon idea: let's package one entangled photon in each pair into a ship container that is sent over the ocean to the destination point. These photons will be used by the encrypting algorithm to check that no tampering is taking place during the transmission. To dispatch entangled photons across the ocean Steven has thought about the possibility of using modified diamond crystals in which a carbon atom is replaced by a nitrogen atom. This leads to a "vacancy" of an electron that can be used to store the entangled photon in a superposition (quantum) state for long period of time as long as it is kept at around 4 degrees K.

Since in a diamond crystal there are billions and billions of atoms you can theoretically store billions of entangled photos... Simon even did some calculation: a ship container has 40 cubic meters of space. 1 cubic meter will be used by crystals to store the entangled photons and the remaining 39 cubic meters are just what is needed to contain the refrigerating equipment to keep the temperature at 4°K.

It really seems like science fiction and what is most amazing is that it is actually science, although it will take some time before seeing this idea becoming practical!

Author - Roberto Saracco

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