Free randomness can be amplified

@article{Colbeck2012FreeRC,
  title={Free randomness can be amplified},
  author={Roger Colbeck and Renato Renner},
  journal={Nature Physics},
  year={2012},
  volume={8},
  pages={450-454}
}
Bell’s equations enable scientists to test the fundamental implications of quantum physics. A central tenet of this idea is that the choice of measurement is truly random. Researchers now show that some Bell experiments can even increase randomness in cases where choice is not entirely free. The concept could increase the usefulness of weakly random sources for more thorough tests of quantum mechanics. 

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References

SHOWING 1-10 OF 37 REFERENCES
Free will and quantum mechanics
A simple example is provided showing that violation of free will allows to reproduce the quantum mechanical predictions, and that the Clauser-Horne parameter can take the maximum value 4 for a proper
Hidden variable models for quantum theory cannot have any local part.
TLDR
This Letter shows the existence of (experimentally verifiable) quantum correlations that are incompatible with any hidden variable model having a nontrivial local part, such as the model proposed by Leggett.
No extension of quantum theory can have improved predictive power
TLDR
This work says that no extension of quantum theory can give more information about the outcomes of future measurements than quantum theory itself, under the assumption that measurements can be chosen freely.
Experimenter's freedom in Bell's theorem and quantum cryptography (7 pages)
Bell's theorem states that no local realistic explanation of quantum mechanical predictions is possible, in which the experimenter has a freedom to choose between different measurement settings.
Wringing out better Bell inequalities
Abstract Local realism implies constraints on the statistics of two physically separated systems. These constraints, known collectively as Bell inequalities, can be violated by quantum mechanics. We
Going Beyond Bell’s Theorem
Bell’s Theorem proved that one cannot in general reproduce the results of quantum theory with a classical, deterministic local model. However, Einstein originally considered the case where one could
Quantum nonlocality as an axiom
In the conventional approach to quantum mechanics, indeterminism is an axiom and nonlocality is a theorem. We consider inverting the logical order, making nonlocality an axiom and indeterminism a
Random numbers certified by Bell’s theorem
TLDR
It is shown that the non-local correlations of entangled quantum particles can be used to certify the presence of genuine randomness, and it is thereby possible to design a cryptographically secure random number generator that does not require any assumption about the internal working of the device.
Violation of local realism with freedom of choice
TLDR
This paper presents an experiment that violates Bell’s inequality while simultaneously closing the locality loophole and addressing the freedom-of-choice loophole, also closing the latter within a reasonable set of assumptions.
The Free Will Theorem
On the basis of three physical axioms, we prove that if the choice of a particular type of spin 1 experiment is not a function of the information accessible to the experimenters, then its outcome is
...
1
2
3
4
...