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Nature publishes the results of the global experiment The Big Bell test

The project is notable for having enjoyed the participation of more than 100,000 people around the world. Also, its conclusions will make it possible to communicate in a way that is impossible to spy on in the future

University of Seville

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IMAGE: For the first time, the thousands of decisions which each experiment requires were taken directly by humans, and not by machines. For this, the thirteen experiments had the help of... view more 

Credit: The Institute of Photonic Sciences

The review Nature has published an article, one of the authors of which was the University of Seville teacher Adán Cabello, which collects the results of the thirteen experiments carried out in November 2016 as part of the Big Bell Test project. For the first time, the thousands of decisions which each experiment requires were taken directly by humans, and not by machines. For this, the thirteen experiments had the help of more than 100,000 people. The Big Bell Test experiments will make it possible to communicate in a way that is impossible to spy on in the future.

On November 30th 2016, simultaneously in Australia, China, Austria, Germany, Switzerland, Italy, France, Spain, Argentina, Chile and the United States, thirteen quantum physics experiments were carried out using photons, atoms and superconducting devices in order to test the breaking of Bell's inequality, a limit discovered by the physicist John Stewart Bell. Breaking Bell's inequality shows us that in nature there are correlations between separate systems that cannot be explained by supposing that experiments reveal pre-existing properties.

The University of Seville has collaborated in one of the thirteen experiments, the Bell test with entangled photons in a temporary container carried out at the University of Concepción in Chile. Among the contributions of the Big Bell Test, Cabello highlights, "the curious thing is seeing how very different physical systems, simultaneously subjected to very different questions in different parts of the planet, all follow exactly the same laws".

The novelty of these thirteen simultaneous experiments is that, for the first time, the thousands of decisions that each experiments require were taken directly by humans, and not by machines or physical devices that could be "in cahoots" with photons or atoms. For this, the thirteen experiments had the help of more than 100,000 people who, via the internet and using games and infrastructures created by the Institute of Photonic Sciences in Castelldefels (Barcelona), generated incredibly long sequences of zeroes and ones which told each laboratory what measurements they had to take. For this reason, 'The BIG Bell Test, exceeded all the scientists' expectations'.

The results of each and every one of the experiments who that Bell's limit was overcome, so confirming the predictions of quantum physics. Beyond the scientific results themselves, the initiative, known as the Big Bell Test, showed how global networks can allow tens of thousands of people to directly participate in cutting-edge scientific research.

The University of Seville teacher Adán Cabello believes that this is "probably the biggest experiment in the history of physics, if we measure it by the number of participants" and "it shows, in a way never seen before, that science is a collective business, which belongs to all of humanity".

The Bell tests mean that it will be possible in the future to have metropolitan communications that are impossible to spy on. "Quantum physics makes secure communications possible", Cabello explains. These communications are based on the laws of nature, and so it is impossible to break them. "The experiments show the best that spies could do" to intercept these communications. If these limits are surpassed, it will be possible to have communication which are impossible to intercept. However, the researchers warn that there is a long way to go before these ideas can be brought into practice.

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