# Quantum mechanics: To be or not to be local

@article{Aspect2007QuantumMT, title={Quantum mechanics: To be or not to be local}, author={Alain Aspect}, journal={Nature}, year={2007}, volume={446}, pages={866-867} }

The experimental violation of mathematical relations known as Bell's inequalities sounded the death-knell of Einstein's idea of 'local realism' in quantum mechanics. But which concept, locality or realism, is the problem? Most of us, most of the time, can get along in life and in science with a sturdy concept of what is 'real'. Generally speaking, an external reality exists independent of observation. But in the world of quantum physics, where individual events are predicted only in terms of…

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## References

SHOWING 1-10 OF 15 REFERENCES

An experimental test of non-local realism

- Physics, MedicineNature
- 2007

This work shows by both theory and experiment that a broad and rather reasonable class of such non-local realistic theories is incompatible with experimentally observable quantum correlations, and suggests that giving up the concept of locality is not sufficient to be consistent with quantum experiments, unless certain intuitive features of realism are abandoned.

Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?

- Physics, Computer Science
- 1935

Consideration of the problem of making predictions concerning a system on the basis of measurements made on another system that had previously interacted with it leads to the result that one is led to conclude that the description of reality as given by a wave function is not complete.

Classical interventions in quantum systems. II. Relativistic invariance

- Physics
- 2000

If several interventions performed on a quantum system are localized in mutually spacelike regions, they will be recorded as a sequence of ``quantum jumps'' in one Lorentz frame, and as a different…

Nonlocal Hidden-Variable Theories and Quantum Mechanics: An Incompatibility Theorem

- Physics
- 2003

It is argued that among possible nonlocal hidden-variable theories a particular class (called here “crypto-nonlocal” or CN) is relatively plausible on physical grounds. CN theories have the property…

Violation of Bell's Inequality under Strict Einstein Locality Conditions

- Physics
- 1998

We observe strong violation of Bell's inequality in an Einstein-Podolsky-Rosen-type experiment with independent observers. Our experiment definitely implements the ideas behind the well-known work by…

Proposed Experiment to Test Local Hidden Variable Theories.

- Physics
- 1969

A theorem of Bell, proving that certain predictions of quantum mechanics are inconsistent with the entire family of local hidden-variable theories, is generalized so as to apply to realizable…

Quantum technology: the second quantum revolution

- Computer Science, MedicinePhilosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences
- 2003

A number of examples of research programs that could deliver quantum technologies in coming decades including: quantum information technology, quantum electromechanical systems, coherent quantum electronics, quantum optics and coherent matter technology are discussed.

Violation of Bell Inequalities by Photons More Than 10 km Apart

- Physics
- 1998

A Franson-type test of Bell inequalities by photons 10.9 km apart is presented. Energy-time entangled photon pairs are measured using two-channel analyzers, leading to a violation of the inequalities…

Bell's inequality test: more ideal than ever

- PhysicsNature
- 1999

The experimental violation of Bell's inequalities confirms that a pair of entangled photons separated by hundreds of metres must be considered a single non-separable object — it is impossible to…

Experimental Test of Bell's Inequalities Using Time- Varying Analyzers

- Physics
- 1982

Correlations of linear polarizations of pairs of photons have been measured with time-varying analyzers. The analyzer in each leg of the apparatus is an acousto-optical switch followed by two linear…