Physicists have confirmed that distant particles can actually influence one another and act in strange ways that can not be explained by common sense or, for the most part by the traditional physical laws.
This bizarre behavior is known as entanglement, or quantum entanglement, and despite many experiments show that it exists, this is the first time it was demonstrated with a free test loopholes, proving that Albert Einstein (that defined this behavior as “scary” ) were wrong about quantum mechanics.
According to quantum theory, the nature of a particle does not exist until it is measured, which means that it only exists in a superposition state until someone decides to watch. The particles can also be interlaced, meaning that they are closely linked together no matter the distance that separated – if the state of the particle A, located on the other side of the universe, is changed, the state of the particle B, here in Earth also be instantly.
So this means that when you measure a particle, you are not alone determining its nature in that moment, you are also defining the nature of its entangled partner. It is for this reason that Einstein and many other physicists doubted the existence of quantum entanglement, because it essentially means that information passes between the two entangled particles much faster than the speed of light – possibly an infinite speed.
This last experiment involved physicists from the Netherlands, United Kingdom and Spain, which entangled pairs of electrons separated by a distance of 1.3 km. Led by researcher B. Hensen of Delft University of Technology in the Netherlands, the team measured one of the electrons as a group watched immediately if your partner was affected.
This is known as “Bell experiment” designed in the 1960s by the Irish physicist John Bell to test if there was a more sensible explanation for entanglement. According to the rational view of the world, after a certain distance, the correlation should cease to exist as the particles are too far away to communicate with each other. But according to quantum theory, there is no distance limit.
Over the past 30 years, the Bell experiment was attempted many times, always showing that quantum theory is real. But in all these experiments had gaps – in general the fact that most researchers entangled photons, but could not be measured because of its super-fast nature, making the results inconclusive.
In an attempt to close this gap, many physicists used entangled ions instead of photons. But it opened another gap, because these ions were not sufficiently removed, opening the possibility that the communication was done at a slower speed than light.
The new experiment was able to close these gaps by combining the benefits of photons with electrons, which are easier to measure. To do this, the team entangled spin of two electrons with two different photons. These two electrons were localized in separate laboratories for 1.3 km, while the photons were sent to a third location, and then, separately entangled with each other.
As soon as photons are entangled, bingo, the two original electrons revolve even in remote laboratories. The team conducted 245 experimental tests comparing entangled electrons and report that Bell’s limit is violated, and showing one of the rare times that Einstein was wrong.
The experiment is also a huge step for quantum cryptography, which is a security system hypothetically impossible to be violated, since it depends on entangled particles for verification. [ScienceAlert]