We analyze anomalies in data to test the violation of Bell's inequality for the EPR-Bohm experiment. We found that the experimental correlations for photon polarization have an intriguing property. In the experimental data there are visible non-negligible deviations of probabilities $P_{ ++}^{ \rm{ exp}}(\alpha, \beta), P_{ +-}^{ \rm{ exp}}(\alpha, \beta), P_{ -+}^{ \rm{ exp}}(\alpha, \beta), P_{ --}^{ \rm{ exp}}(\alpha, \beta) $ from the predictions of quantum mechanics, namely, $P_{ ++}(\alpha, \beta)=P_{ --}(\alpha, \beta)= { 1/2}\cos^2(\alpha-\beta)$ and $P_{ +-}=P_{ -+}(\alpha, \beta)={ 1/2}\sin^2(\alpha-\beta).$ However, in some mysterious way those deviations compensate each other and finally the correlation $E^{ \rm{ exp}}(\alpha, \beta)= P_{ ++}^{ \rm{ exp}}(\alpha, \beta)- P_{ +-}^{ \rm{ exp}}(\alpha, \beta)- P_{ -+}^{ \rm{ exp}}(\alpha, \beta)+ P_{ --}^{ \rm{ exp}}(\alpha, \beta)$ is in the complete agreement with the QM-prediction, namely, $E(\alpha, \beta)= P_{ ++}(\alpha, \beta)- P_{ +-}(\alpha, \beta)- P_{ -+}(\alpha, \beta)+ P_{ --}(\alpha, \beta)= \cos 2(\alpha-\beta).$ Therefore such anomalies play no role in the Bell's inequality framework. Nevertheless, other linear combinations of experimental probabilities do not have such a compensation property. There can be found non-negligible deviations from predictions of quantum mechanics. Thus neither classical nor quantum model can pass the whole family of statistical tests given by all possible linear combinations of the EPR-Bohm probabilities. Does it mean that both models are wrong?
Categories: quant-ph