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Testing Bell's inequality with cosmic photons: closing the setting-independence loophole
Jason Gallicchio1, Andrew S Friedman2, David I Kaiser2
1Kavli Institute for Cosmological Physics, University of Chicago, Chicago, Illinois 60637, USA.
Physical Review Letters
|April 8, 2014
Summary
This study proposes using cosmic light sources to test Bell's inequality, significantly reducing loopholes. This method requires coordination over billions of years, strengthening experimental proof against local hidden variables.
Area of Science:
- Quantum mechanics
- Cosmology
- Experimental physics
Background:
- Current Bell's inequality tests are vulnerable to local hidden variable theories.
- Detector settings in existing experiments are influenced by factors established shortly before measurement.
Purpose of the Study:
- To propose a robust experimental scheme for testing Bell's inequality.
- To close loopholes related to the timing of detector settings and local hidden variables.
Main Methods:
- Utilizing photons from causally disconnected cosmic sources (e.g., quasars, cosmic microwave background).
- Employing these photons to determine detector settings in Bell tests.
Main Results:
- The proposed method drastically increases the required timescale for coordination between detector settings and hidden variables.
- This extends the potential coordination timescale from milliseconds to billions of years.
Conclusions:
- Cosmic-based Bell tests offer a significant improvement in closing experimental loopholes.
- This approach provides stronger evidence against local hidden variable theories in quantum mechanics.
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