Abstract
An EPR experiment is studied where each particle undergoes a few weak measurements along some pre-set spin orientations, whose outcomes are individually recorded. Then the particle undergoes a strong measurement along a spin orientation freely chosen at the last moment. Bell-inequality violation is expected between the two final strong measurements within each EPR pair. At the same time, agreement is expected between these measurements and the earlier weak ones within the pair. A contradiction thereby ensues: i) Bell's theorem forbids spin values to exist prior to the choice of the spin-orientation to be measured; ii) A weak measurement cannot determine the outcome of a successive strong one; and iii) Indeed no disentanglement is inflicted by the weak measurements; yet iv) The weak measurements' outcomes agree with those of the strong ones. The most reasonable resolution seems to be that of the Two-State- Vector Formalism, namely, that the experimenter's choice has been encrypted within the weak measurement's outcomes, even before the experimenter themselves knows what their choice will be. Causal loops are avoided by this anticipation remaining encrypted until the final outcomes enable to decipher it.
Highlights
Bell's theorem [1] has dealt the final blow on all attempts to explain the EPR correlations [2] by invoking previously existing local hidden variables
While the EPR spin outcomes depend on the particular combination of spin-orientations chosen for each pair of measurements, Bell proved that the correlations between them are cosine-like and nonlinear Eq (1) these combinations cannot all co-exist in advance
Such a past-to-future effect can be straightforwardly ruled out by posing the following question: How robust is the alleged bias introduced by the weak measurements? If it is robust enough to oblige the strong measurements, it is equivalent to full collapse, namely local hidden variables, already ruled out by Bell's inequality
Summary
Bell's theorem [1] has dealt the final blow on all attempts to explain the EPR correlations [2] by invoking previously existing local hidden variables. Nonlocal effects between the two particles have been commonly accepted as the only remaining explanation It is possible, to explain the results without appeal to nonlocality, by allowing hidden variables to operate according to the Two-State Vector Formalism (TSVF). As this proof is bound to elicit attempts to find loopholes within it, we describe it elsewhere in greater detail and with several control experiments [3]. 4 describes a combination of strong and weak measurements on a single particle illustrating a prediction of TSVF. Consider a large ensemble of N particles, each undergoing two consecutive strong measurements, along the co-planar spin orientations α and β The correlation between their outcomes depends on their relative angle θαβ:. The probability seems to have a definite value which agrees with both outcomes, due to two state-vectors [5], one evolving from the past, t
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