Scientists Just Unveiled The First-Ever Photo of Quantum Entanglement

It might not look like much, but stop and think about it for a second: this fuzzy grey image is the first time we’ve seen the particle interaction that underpins the strange science of quantum mechanics and forms the basis of quantum computing. Quantum entanglement occurs when two particles become inextricably linked, and whatever happens to one immediately affects the other, regardless of how far apart they are. Hence the ‘spooky action at a distance’ description. This particular photo shows entanglement between two photons—two particles of light. They’re interacting and, for a brief moment, sharing physical states. Paul-Antoine Moreau, the first author on the paper where the image was unveiled, told the BBC that the image was “an elegant demonstration of a fundamental property of nature.” To capture the incredible photo, Moreau and a team of physicists created a system that blasted out streams of entangled photons at what they described as ‘non-conventional objects’. The experiment involved capturing four images of the photons under four different phase transitions. You can see the full image below. What you’re looking at here is a composite of multiple images of the photons as they undergo a series of four phase transitions. Essentially, the physicists split the entangled photons and ran one beam through a liquid crystal material known as β-Barium Borate, triggering four phase transitions. They captured photos of the entangled pair undergoing the same phase transitions, even though it had not yet passed through the liquid crystal phase. You can see the setup below; the entangled beam of photons comes from the bottom left. One half of the entangled pair splits to the left and passes through the four-phase filters. The others that went straight ahead didn’t go through the filters but underwent the same phase changes. The camera could capture images of these, showing that they’d both shifted the same way despite being split. They were entangled. While Einstein made quantum entanglement famous, the late physicist John Stewart Bell helped define quantum entanglement and established a test known as the ‘Bell inequality’. If you can break Bell’s inequality, you can confirm genuine quantum entanglement. “Here, we report an experiment demonstrating the violation of a Bell inequality within observed images,” the team writes in Science Advances. “This result both opens the way to new quantum imaging schemes … and suggests promise for quantum information schemes based on spatial variables.” The research was published in Science Advances.