Bell’s inequalities

Philip Cunningham writes to tell us of an interesting experiment by quantum physicist Anton Zeilinger and colleagues that pushed the “free-will loophole” back to 7.8 billion years ago, using quasars to determine measurement settings: Abstract: In this Letter, we present a cosmic Bell experiment with polarization-entangled photons, in which measurement settings were determined based on real-time measurements of the wavelength of photons from high-redshift quasars, whose light was emitted billions of years ago; the experiment simultaneously ensures locality. Assuming fair sampling for all detected photons and that the wavelength of the quasar photons had not been selectively altered or previewed between emission and detection, we observe statistically significant violation of Bell’s inequality by 9.3 standard deviations, corresponding to an estimated p Read More ›

From Mind Matters Today: Succinctly, researchers using Bell’s theoretical insight into quantum entanglement have shown that there are no deterministic local hidden variables. This means that the final state of entangled quantum particles is not determined by any variables in the initial state. Nature at its most fundamental level is indeterminate. The states of bound particles are not determined by any local variable at the moment of separation. Bell’s inequality and the experimental work that has followed on it conclusively demonstrate that quantum entanglement, and thus nature, is not determinate, at least locally. There remains the remote possibility of non-local determinism, but that view is considered fringe and is rejected by nearly all physicists working in the field. It is Read More ›