A group of researchers from the University of Glasgow, in a study published in Science Advances, claims to have for the first time taken the picture of quantum entanglement, an elusive and in some ways still mysterious phenomenon that Einstein himself had nicknamed “action spectral distance.”
This phenomenon predicts that two particles, once they have interacted in a certain way, in a certain sense remain “connected” whatever the distance between them. While not fully understanding the phenomenon, today quantum entanglement is also exploited in practical applications, especially in quantum computing and quantum cryptography. However, despite being applied in these fields, an image that incorporates this physical state has never been realized.
To do this, researchers from the School of Physics and Astronomy of the University of Glasgow have carried out “an experiment that demonstrates the violation of a Bell inequality within the observed images,” as can be read in the study abstract, an experiment that “is based on the acquisition of images at full-field coincidence of a phase object probed by photons from an entangled pair source.”
Essentially they fired a stream of entangled photons towards “unconventional objects” from a quantum source of light. A special super-sensitive camera, so sensitive that it can also detect individual photons, has captured the image of both the photon and its “twin” with which it was connected.
According to Paul-Antoine Moreau, one of the authors of the study, it is “an elegant demonstration of a fundamental property of nature, seen for the first time in the form of an image.”