We may not notice it now, but it is entirely possible that, in distant future historians will be mentioning 2015 A.D. with a sense of awe. I can clearly imagine a starry-eyed kid of future thinking how wonderful it must have been to be alive when quantum entanglement (QE) was proven with no communication/detection loophole.
QE can’t be explained in simple words (if I succeed, I can surely hope to get, if not a Nobel, at least the Pulitzer Prize for it!) but it exists because our universe allows objects to go about in pairs with an inexplicable interconnectedness. Such twined pairs appear to be so entangled with each other that changing one instantaneously changes its counterpart, even if they are far apart from each other. This makes it appear as if QE is a phenomenon free from the bounds of both time and space!
It is this instantaneous change over any distance that has troubled scientists accustomed to living in a universe where nothing travels faster than light, not even information. So QE has been a real bugbear for the physicists since its shadowy presence was felt.
Einstein, when forced to accommodate the idea of QE, blamed it on (what he called) hidden variables, some sort of pre-existing qualities that we don’t have access to; but, soon John Bell proved that no hidden variables can account for correlation beyond a certain limit and the hunt for detecting QE began in earnest across the globe.
Unfortunately for physicists, the search was not straight forward as the entanglement is not just difficult to observe, particles indulging in it are very fickle. This means that, in any experiment conducted, most of the participating particles are lost, making the statistical dependability of the results questionable. This made proving existence of QE to the extent that there is no detection loophole the most difficult (but highly coveted) quest of modern experimental physics.
Recently, a team led by Ronald Hanson of Delft University, Netherlands, conducted an experiment using electrons entangled with photons that detected entanglement of statistically satisfactory level to claim to be free of detection loopholes. As this experiment involved pairs of electrons located over 1.3 KM distance, it also closed the communication loophole (i.e. a possibility of slower-than-speed-of-light transfer of information between them).
So, we now live in a universe with quantum entanglement. But does it change anything?
At a practical/mundane level, the immediate possibility it opens up is that of technologies that will provide us a 100 percent secure, un-hackable communication network/internet. As QE is completely observer-sensitive, it can immediately detect eavesdropping. In a world that is getting paranoid about security, QE is the ultimate solution.
In not too far future, the interconnectedness provided by QE can also be used for sci-fi celebrated teleportation, as by entangling all your molecules with another set of molecules over a distance, it will be possible to transport a perfect twin over a distance instantaneously.
Even if these technological possibilities boggle the mind, it is the philosophical impact QE has that is more awe-inspiring. Presence of this entanglement opens up an aspect of the reality that questions our understanding of reality. There exists interconnectedness, almost mystical in nature, that we can’t understand the mechanism of.
We now know that the entanglement exists, but we have no clue how and why. It questions our understanding of time and space as it transcends both these dimensions that our existence is locked in.
Our future in this universe has taken a new turn. Quantum entanglement could be the route to real freedom, from the physical limitations of the reality and into the unknown free from when and where.