Test looks at ‘Spooky action at a distance’

Oct. 1, 2008
Researchers at the University of Geneva (Geneva, Switzerland) have determined a minimum speed for Albert Einstein’s hypothetical “spooky action at a distance” (see Salart et al.

Researchers at the University of Geneva (Geneva, Switzerland) have determined a minimum speed for Albert Einstein’s hypothetical “spooky action at a distance” (see Salart et al., Nature, p. 861, Aug. 14, 2008). Two pre—existing underground fiber—optic paths, extending east and west from Geneva over 18 km, were equalized in length by adding a fiber coil to one of the paths. Identical unbalanced fiber—optic Michelson interferometers were added to each end. Entangled photon pairs generated in Geneva in a nonlinear crystal were sent each way to the interferometers.

Using two optically identical setups (but scanning the phase of one interferometer only), the researchers measured the correlation between the two photon detections over many Earth rotations. They were able to exclude any “common cause” explanation for the correlations, and, assuming that the Earth’s speed relative to a privileged frame is less than a thousandth of the speed of light, determined that a spooky action at a distance had to travel at 10,000 times the speed of light or more. Another explanation is that spooky action at a distance doesn’t exist and quantum physics is correct. Contact Daniel Salart at [email protected].

Sponsored Recommendations

March 31, 2025
Enhance your remote sensing capabilities with Chroma's precision-engineered optical filters, designed for applications such as environmental monitoring, geospatial mapping, and...
March 31, 2025
Designed for compatibility with a wide range of systems, Chroma's UV filters are engineered to feature high transmission, superior out-of-band blocking, steep edge transitions...
March 31, 2025
Discover strategies to balance component performance and system design, reducing development time and costs while maximizing efficiency.
March 31, 2025
Explore the essential role of optical filters in enhancing Raman spectroscopy measurements including the various filter types and their applications in improving signal-to-noise...

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!