Quantum leaps

Often referred to as the future of computing, quantum computing is based on exploiting the laws of quantum mechanics to transfer information using ‘qubits’. At the International Conference on Quantum Cryptography (QCrypt), held on Sept. 12, at the Carnegie Institution for Science in Washington, D.C., several research teams presented their findings in the field of quantum computing.

‘Qubits,’ or quantum bits, are the smallest unit of information in a quantum computer. They store data that is traditionally binary in the form of two distinguishable quantum states. The general principle behind storing information is that these quantum bits have properties like superposition and entanglement. Superposition is the ability of these qubits to have more than a single state at the same time, which means that, in the case of an electron, it is possible for it to be in the ‘up’ and ‘down’ state at once. Entanglement is the inexplicable phenomenon of quantum particles to be in ‘sync’ with each other, even at great distances.

However, the existence of a fully functional quantum computer is still years away. This is because of the fact that it is a significant challenge to make qubits behave in a certain way when even the slightest disturbance causes qubits to fall out of their state. Another concern is that even though they have entanglement states at larger distances, those distances are finite and information needs to be repeated after some threshold value when using physical transfer methods. In free space, less information is lost, scattered, or absorbed.

A group of researchers from the University of Calgary in Canada reported that they had transferred quantum states successfully over a distance of 6.2 km using three spaced out stations — A, B, and C — to send states from A to C using the Calgary fiber network. One of the interesting things that the report notes is that, even though they send disembodied quantum states from A to B, B doesn’t receive any physical particle, but still sends out photons in entanglement states. Another team reports the construction of a 30 km optical fiber-based quantum network distributed over a 12.5 km area in the city of Hefei, China. According to the report, the network is as completely robust in the real world scenario and employed stabilization strategies. Both of these findings were published in Nature Photonics on Sept. 19.

A research team from the Delft University of Technology in the Netherlands developed a system of quantum memory using quantum entanglement of electrons in diamond chips. Moving the entanglement of electrons to atomic nuclei protects the states, which is a rule that could potentially be used to expand the range of quantum networks, according to a scientist on the team.

As research teams continue to work on quantum computing, they find better ways to control quantum bits and make stronger, larger, more functional quantum networks. Quantum computing could revolutionize computing simply because it is so much faster than traditional methods. One way to think about this is that factoring large numbers, which is one of the slowest calculations that traditional computers do, could be done in a significantly shorter, more feasible time.

Furthermore, entanglement allows researchers to know when the data is being modified or accessed, because tweaking one qubit allows another that is far away to also change, which security systems can catch and relate to unauthorized access. Thus, another benefit of quantum computing is that it allows for better security of data transfer.