Scientists have used 100,000 people playing a special video game to test principles of quantum mechanics. On November 30th, 2016, more than 100,000 people all around the world used their smartphones and other internet-connected devices to play a video game, the results of which determined how entangled atoms, photons, and superconducting devices were measured in twelve laboratories around the world.
Scientists used a large amount of random human input, to test Einstein's principle of local realism. The results of the global experiment have just been published in the journal Nature.
In the experiment named after physicist John Bell, pairs of entangled particles such as photons are generated and sent to different locations, where particle properties such as the photons' colors or time of arrival are measured.
Spooky particles confound Einstein
If the measurement results tend to agree, regardless of which properties measured, it points towards something very surprising: either the measurement of one particle instantly affects the other particle (despite being far away), or even stranger, the properties never really existed, but rather were created by the measurement itself.
Both of this possible results contradict long-held theories developed by Einstein called Local Realism. Local Realism is based on an understanding that our universe is independent of our observations, in which no influence can travel faster than light.
By getting participants to randomly choose the measurements, by playing a basic video game that has limited options, the experiment avoided the so-called "freedom-of-choice loophole" which is the possibility that the particles to be measured may influence the choice of measurement. If this influence does exist it would invalidate the test.
Likewise, the decision can’t be made by a dice or random number generator as there is the possibility these physical systems are coordinated with the entangled particles. The experiment was led by ICFO-The Institute of Photonic Sciences, in Barcelona.
Video game players all over the world contribute to science
The experiment recruited its human participants through a wide online marketing campaign that included podcasts and videos. Each player would contribute an unpredictable sequence of bits (zeros and ones) by playing an online video game.
The results were then sent to experiments in Brisbane, Shanghai, Vienna, Rome, Munich, Zurich, Nice, Barcelona, Buenos Aires, Concepción Chile and Boulder Colorado. The random input of players was used to set the angles of polarizers and other laboratory elements to determine how entangled particles were measured.
Each of the twelve labs carried out a different experiment to test local realism in different physical systems and to test other concepts related to realism. The results, now finally analyzed two years after the experiment disagree with Einstein's Local Realism, the results also open up several new ways to think about the study of Entanglement.
Morgan Mitchell, leader of the BBT project and ICREA Professor at ICFO says, "What is most amazing for me is that the argument between Einstein and Niels Bohr, after more than 90 years of effort to make it rigorous and experimentally testable, still retains a human and philosophical element. We know that the Higgs boson and gravitational waves exist thanks to amazing machines, physical systems built to test the laws of physics. But local realism is a question we can't fully answer with a machine. It seems we ourselves must be part of the experiment, to keep the Universe honest."