14 DAY TRIAL // Photon entanglement is believed to be the future of quantum computing, however creating entangled photon pairs is extremely difficult because entangled photons generation is subjected to random quantum processes. This basically means that with a device you can create a single entangled pair while in a later identical setting one wouldn't be able to create any. Secondly, entangled pairs become useless once tested.
Technion-Israel Institute of Technology physicist Yosi Avron believes that he may have found a way to improve entangled photon generation through a technique called switch path ambiguity. Elementary particles experience what we call particle-wave duality, meaning that they may appear whether as a particle or as a wave at the same time. Although it is hard for us to believe that this actually takes place, all objects experience particle-wave duality to some extent, no matter how massive.
Thus, elementary particles may be at two places at once. The phenomenon can be easily observed in interference patterns, when photons of light are sent towards a target bearing two slits. Instead of choosing one of the two, the photon actually passes through both slits at the same time. The analogy to the real world is pretty simple. Imagine two goals on a football pitch place next to each other on the same line. If we were to be subjected to quantum laws on a macroscopic scale, then a player shooting at one of the goals will score in both with a single ball.
By setting multiple different paths for the photons to follow, Avron believes that two states with the same result may be created, in order to form entangled photons by reducing the random quantum processes.
"If you have a system with an atom, you start it in an excited state. Then it relaxes and releases a photon at an intermediate state. Then it relaxes more and releases a photon at the ground state. The ambiguity comes in when we create a second intermediate state, identical to the first, so that you have a state where two photons are generated in alternative ways," said Avron.
However, the problem is that "it is difficult to get two states that are precisely identical like that," he says. "The states have slightly different energies and this adversely affects entanglement."
A more likely situation would be that in which the timing of the system is re-arranged, so that identical entangled photons are obtained every time, without suffering from the quantum mechanics effects while testing entangled photons.
"We think that it is possible to design an experiment to test it. David Gershoni is working on such an experiment. It has been difficult to get high quality entanglement on demand, and what we have discovered is that it is possible and something that we can do in a few years' time," added Avron.