A team of Australian and German researchers have got together to create a genetic algorithm that confirms the rejection of classical notions of causality. “Bell’s theorem excludes traditional concepts of causality and is now a cornerstone of modern physics. But despite the fundamental importance of this theorem, only recently was the first ‘loophole-free’ experiment reported which convincingly verified that we must reject classical notions of causality,” said Dr. Alberto Peruzzo from RMIT University in Melbourne. He continued, “Given the importance of this data, an international collaboration between Australian and German institutions has developed a new method if analysis to quantify such conclusions robustly.”
The team decided to use genetic programming to automatically find those models that matched closest to the data they held. When they applied machine learning to find the closest classical explanations of experimental data, they were able to map out many dimensions of the departure from the classical that is exhibited in quantum correlations. Dr. Chris Ferrie, from the University of Technology, Sydney, said, “We’ve light-heartedly called the region mapped out by the algorithm the ‘edge of reality,’ referring to the common terminology ‘local realism’ for a model of physics satisfying Einstein’s relativity. The algorithm works by building casual models through simulated evolution is imitating natural selection – genetic programming. The algorithm generates a population of ‘fit’ individual casual models which trade off closeness to quantum theory with the minimization of casual influences between relativistically disconnected variables.”
Photons were used in the experiment to generate the quantum correlations that can’t be explained using classical mechanics. They were prepared in different states possessing quantum entanglement, and the data was then collated and used by the algorithm to find the closest matching model. The model then quantifies the region of models that nature itself rules out.
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