The world of Quantum Mechanics, the part of physics that studies how light and matter behave on the smallest scales, could not be more puzzling. It is full of realities familiar to scientists but "impossible" for the rest of us mortals. One of them is what Einstein called the “spooky reaction at a distance”, a phenomenon that allows photons to “communicate” with each other instantly , no matter how far away they are: it is called quantum entanglement.
Top Image: On the left, sample of GFP, on the right, its origin: some jellyfish - Northwestern University
Recently, research published in Nature Communications has succeeded in creating, for the first time, quantum entanglement from a biological system . A study led by Prem Kumar, a researcher at Northwestern University (Illinois, USA) has managed to link the polarity of two photons released by a protein, the « Green Fluorescent Protein » or GFP, at a distance.
This could open the door to developing biological tools capable of taking advantage of Quantum Mechanics or expanding knowledge about living systems.
"Can we use quantum tools to learn about biology?" Prem Kumar asked in a statement. “Many have asked this same question for a long, long time, since the birth of Quantum Mechanics. The reason we are so interested in this is because it could allow us to develop applications that would otherwise be unthinkable ."
Some 75 years ago, Nobel laureate Erwin Schrödinger , famous for his quantum cat , wondered if Quantum Mechanics had any role in biology. That is, if the particles that are part of living beings have a quantum behavior that influences their operation. There is no clear answer yet, but Kumar's research points in the direction of yes.
A quantum and biological machine?
In this study, the researchers used GFPs, proteins routinely used in research, and characterized by emitting fluorescence and coming from jellyfish. From them, they tried to make the photons they emitted exhibit the phenomenon of quantum entanglement, through their interaction with other light waves to "tune" them.
Thanks to this, the researchers achieved that when measuring the state of two separate and different photons, the result was always the same . This is precisely how it works in quantum communication and quantum teleportation of information , and also in the development of future quantum computers.
For this reason, many scientists are working on creating larger and larger entangled quantum systems composed of more atoms or photons. Kumar's lab has tried to do something similar but from a biological substrate: in this case a protein.
In this case, the authors managed to entangle the polarity of pairs of photons. They also found that the structure of the protein is capable of preventing the entanglement from being lost by its interaction with the environment.
'When I measured the vertical polarization of one particle, I knew the result would be the same for the other,' explained Prem Kumar. “If you measured the horizontal polarization, you could predict the horizontal polarization of the other. Ultimately, we created an interlocking state that correlated all possibilities simultaneously."
Once they have shown that it is possible to create quantum entanglement from biological particles, the researchers will try to build a quantum machine with a biological substrate. Later, they will try to find out if this system can be more effective than the artificial ones.
Reference: Generation of photonic entanglement in green fluorescent proteins