For some time now, scientists and researchers have been toying with the concept of machinery that relies on quantum mechanics. Today, Richard Hughes at Los Alamos National Labs in New Mexico revealed an alternative quantum internet, which they say they have been running for two and half years. Image: Blitz by artist Tom Estes
The Government Lab at Los Alamos are now highly confident of the efficacy of its quantum internet having run this system now for over two years. Their approach was to create a quantum network based around a hub and spoke-type network.
Basically, the idea revolves around “quantum teleportation”, a process where quantum states of matter, rather than matter itself, are beamed from one location to another. Currently, this involves using a high-powered laser to fire entangled photons from one location to the next. When the photons at the receiving end take on the properties of the photon sent, a quantum teleportation has occurred, a process which is faster than the speed of light since matter is not actually moving, only its properties. All messages get routed from any point in the network to another via a central hub.
The big advantage of this system is that it makes the technology required at each node extremely simple essentially little more than a laser. In fact, Los Alamos has already designed and built plug-and-play type modules that are about the size of a box of matches. “Our next-generation will be an order of magnitude smaller in each linear dimension,” they say. Their ultimate goal is to have one of these modules built in to almost any device connected to a fibre optic network, such as set top TV boxes, home computers and so on, to allow perfectly secure messaging.
As long as the hub is secure, then the network should also be secure. The problem with this approach is scalability. As the number of links to the hub increases, it becomes increasingly difficult to handle all the possible connections that can be made between one point in the network and another. Of course, the network can never be more secure than the hub at the middle of it and a pure quantum internet should allow perfectly secure communication from any point in the network to any other.
Hughes and his co-workers say they have solved this- not with photon detectors which are expensive and bulky but by equipping each node in the network with quantum transmitters or laser. The idea is that messages to the hub rely on the usual level of quantum security. So although all nodes can send and receive messages in a normal way only the hub is capable of receiving a quantum message. However, once at the hub, they are converted into conventional bits and then reconverted into quantum bits to be sent on the second leg of their journey. The hub can then route this message to another node using another one time pad that it has set up with this second node. So the entire network is secure, provided that the central hub is also secure.
This is not the first time this kind of approach has been tried. Two years ago, scientists set the record for the longest teleportation by beaming a photon some 16 km. However, last year, a team of international researchers was able to beam the properties of a photon from their lab in La Palma to another lab in Tenerife, some 143 km away. Not only was this a new record, it was significant because 143 km happens to be just far enough to reach low Earth orbit satellites, thus proving that a world-spanning quantum network could be built. According to MIT Technology Review shortly there the discovery at La Palma, Juan Yin at the University of Science and Technology of China in Shanghai announced an advance, conducting the first teleportation of quantum states between two rubidium atoms. Naturally, atoms are several orders larger than a quantum qubit, which qualifies them as “macroscopic objects” – i.e. visible to the naked eye. This in turn led many to believe that large quantities of information could be teleported from one location to the next using this technique. The trick to teleportation comes from a quirk of quantum mechanics that allows you to create two particles that are completely in tune with one another, which are known as an entangled pair.
Let’s say you have two entangled photons and you are measuring their polarization, or the direction in which they are oscillating. If one photon has a vertical polarization, you know the other one is going to be exactly the same. The trouble is that quantum mechanics works on probability – before you measure a particle’s polarization it is equally likely to be horizontal or vertical. According to the standard interpretation of quantum mechanics, particles exist in some strange simultaneous vertical/horizontal state until you make a measurement. With an entangled pair, you can just measure one particle, and no matter how far away the other one is from the first, it will instantly gain whatever property you measured.
And then came another breakthrough from Toshiba Research and Cambridge University in England, where researchers managed to transmit qubits and binary data down the same piece of optic fiber. This laid the groundwork for a conventional internet that runs via optic cable instead of satellites, and which could be protected using quantum cryptography, a secured means of information transfer which in theory remains unbreakable. And finally, the companies of IBM and the University of Southern California reported big advances in the field of quantum computing during 2012. The year began with IBM announcing that it had created a 3-qubit computer chip capable of performing controlled logic functions. USC could only manage a 2-qubit chip which was fashioned out of diamond. Both advances strongly point to a future where your PC could be either completely quantum-based, or where you have a few quantum chips to aid with specific tasks.
If developed, quantum teleportation satellites could allow spies to pass large amounts of information back and forth or create unhackable codes. Quantum computers – which would be smaller and exponentially more powerful than modern computers and able to model complex phenomenon, rapidly crunch numbers, and render modern encryption keys useless would need quantum teleporters in order to be networked together in a quantum version of the internet.China plans to launch a satellite with a quantum yeleportation experiment payload in 2016 and the European, Japanese, and Canadian space agencies are hoping to fund their own quantum teleportation satellite projects in the coming years.