Abstract
Exploiting the tension between the two dynamics of quantum theory (QT) or the
so-called "measurement problem" of QT within a modified version of Wigner's
Friend thought experiment, we point out that two different descriptions of
Friend's lab by two different observers, Wigner and his Student, applying the
same textbook QT can lead to inconsistency in observed probabilities. To avoid
such inconsistent predictions of QT, we hypothesize two distinct solutions
inspired by the perspectives of Wigner and Student, which we term as
Äbsoluteness of measurement (AoM)", and "Non-absoluteness of measurement
(NoM)". To test the validity of these two perceptions in an operational
approach, we construct an extended Wigner's Friend scenario and probe two sets
of empirical probabilities inferred from these two perceptions without assuming
the details of the experiment. We show that the set of probabilities obtainable
for NoM is strictly larger than the set obtainable for AoM. We then further
extend our scenario for two spatially separated Friends and propose an
operational task with a suitable figure of merit to single out quantum
correlations achievable with NoM but cannot be achieved using AoM. Notably, the
optimal value of the figure of merit in QT with AoM is the same as in classical
theory. We also analyze whether different interpretations of QT are compatible
with these two perceptions and provide consistent predictions or not. Finally,
we point out that the recent no-go theorems of QT provided by Frauchiger-Renner
Nat. Commun. 9, 3711 (2018), by Brukner Entropy 20, 350 (2018), and by K.W.
Bong et al., Nat. Phys. 16, 1199 (2020) are particular instances of the
violation of AoM.
Users
Please
log in to take part in the discussion (add own reviews or comments).