Violation of Bell’s inequalities
Bragg diffraction on standing waves


The Aspect’s experiment outcome is the key evidence to demonstrate the violation of Bell’s inequalities.  The experiment in question was performed by A. Aspect and his co-workers in three variations. In the paper herein, the third variation of the experiment, where a light switch was used to change polarisation of photons, is to be described.  Switching the beam of photons was based on the Bragg diffraction phenomenon on ultrasound waves. An experimental proof of the violation of the Bell’s inequalities has a crucial value in solving the Einstein - Bohr dispute on the nature of light.  The Aspect’s experiment and other papers on entangled states were honoured by being awarded the Nobel Prize in Physics in 2022 for Alain Aspect, John F. Clauser and Anton Zeilinger.


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