Quantum entanglement is a ghostly phenomenon whereby two particles — say, photons — become mysteriously entwined, such that changes in the states of one particle also simultaneously occur in the other, even if the two particles are separated by great distances. Einstein was so disconcerted by the phenomenon that he called it "spooky," and although quantum entanglement has been definitively established as a real phenomenon, scientists still don't really understand how to make sense of it.

One of the reasons that entanglement is probably so difficult to grasp is that the phenomenon is only supposed to happen on the quantum level, with fundamental particles and such. It isn't supposed to happen on the macro-level of our everyday experience. Chairs and tables don't ever randomly become quantum entangled. Neither do living things. Then again ...

Scientists recently looked back at a study from 2016 that was performed on photosynthetic green sulfur bacteria. The experiment wasn't designed to look for quantum interactions; it was designed to study how the photosynthetic organisms interact with and absorb light that bounces between mirrors. But upon second look at the study, scientists noticed something, well, funny. The bacteria appear as if they had become entangled with the light that was bouncing between them, reports Scientific American.

"Our models show that this phenomenon being recorded is a signature of entanglement between light and certain degrees of freedom inside the bacteria," said quantum physicist Chiara Marletto, who oversaw the new analysis.

How the experiment worked

Basically, it appears that certain photons in the experiment were both hitting and missing photosynthetic molecules within the bacteria at the same time. This kind of simultaneous behavior is what you would expect to see if there's entanglement happening.

It's a surprising and mind-bending possibility. If confirmed, this would be the first time a life form was found to operate according to quantum principles, and it would open up a whole can of theoretical worms. Might quantum mechanical properties be at play across the biological world? Might natural selection have come up with ways for living systems to naturally exploit quantum phenomena? And if so, how might this change our understanding of biological processes?

Of course, this is all a very big "if" at the moment. This experiment, while compelling, was not designed to test for quantum phenomenon, and there are flaws in the design if we want to truly test a quantum hypothesis. Researchers will need to go back to the drawing board with a new aim in mind. Until then, any conclusions are speculative at best. But this could also be the beginning of a whole new way of looking at how the micro and macro worlds interact, and how they are related.

Experiment might have caused 2 living things to get quantum entangled
Scientists revisiting a 2016 experiment about photosynthetic bacteria discover the bacteria got entangled in the light.