The study of quantum phenomena within living beings is extremely difficult to implement and it is a mostly unexplored field.
Quantum mechanics is complicated stuff – at least on this, I don’t fear being disproved. Particles that in reality are waves, objects that are in multiple places simultaneously, particles that pass through walls, cats alive and dead at the same time, etc… Richard Feynman, a true genius of ‘900 physics, used to say that nobody really understood quantum mechanics. And, rightfully, facing this difficulty, physicists try to simplify their lives when attempting to experiment with a quantum phenomenon in a laboratory. Typically, this implies working at extremely low temperatures (touching -273°, near absolute zero), to avoid other particles’ thermic vibration; using vacuum chambers with extremely low pressures, as to bypass any pollution coming from air or other rubbish that could compromise the object of study; often using platforms that can absorb any external vibration; sometimes using tools hundreds of times thinner than a human hair. Despite all of this, we are only able to observe phenomena that are, shall we say, ‘simple’. Around us (as well as within), monstrously more complex, chaotic, and random events happen at all times, than those analyzed in a laboratory. They are so complex that we are not able to explain them through equations that are elementary, transparent, and clear enough to be grasped by the human mind. Science has always had a reductionist tradition through which complex systems are fragmented in their most basic components until they become comprehensible.
And what is found in the opposite extreme of the cold, well-controlled, aseptic environment that physicists love to replicate? Life. Life is warm, complicated to explain, dirty, and wet. While discussing the origins of life, Charles Darwin imagined a «warm little pond», surely not an ultra-high-vacuum depressurized chamber, cold and uncontaminated. Therefore, it is not surprising that the study of quantum phenomena within living beings is extremely difficult to implement and it is a mostly unexplored field.
Nevertheless, a group of scientists decided to take the challenge and attempted to put a living being in one of the most peculiar quantum states. The chosen test subject was a tardigrade, also known as ‘water bear’ – a minuscule animal, but particularly coriaceous. It resembles a hybrid of a gummy bear and a caterpillar, its length is less than 1 mm, and it resists everything: it can survive temperatures above 100°, as well as lower than -200°, it survives extremely high radiation levels and, despite being aquatic, it can live through decades if desiccated. It can be found in all continents – including Antarctica – from the depths of the abyss, all the way to the Himalayan mountains. The European Space Agency has even taken some specimens into space to see how they would manage out there, with no astronaut suit: in this case too, they showed hard skin , so much so that some are thinking of using them to transport life out of our planet . In other words, the overused expression ‘resilient’ is worth using to describe this tiny animal.
Going back to the experiment, the scientists’ idea is to put one of these water bears in a state of “entanglement”. Entanglement is maybe one of the most mysterious phenomena of quantum mechanics, which has been a challenge for physicists for decades. In this article, we have no possibility of delving into a detailed description of it, so let’s at least try to outline it. Imagine a quantum system of two particles. Both particles have an arrow drawn on them. The particles restlessly rotate, continuously pointing their arrow in every direction. However, as soon as we stop one of the particles and observe in which direction the arrow is pointing, the other particle automatically stops as well, pointing its arrow in the opposite direction. This, roughly speaking, is entanglement: a connection between quantum objects, in which by measuring one we instantly modify the other as well, no matter whether they are at the opposite poles of the universe. Usually, scientists are able to entangle photons (the particles that transport light) or other particles like electrons, etc… The challenge is to entangle increasingly bigger objects, and in always less controlled environments (pressure, temperature, etc…). In this manner, succeeding to use a living animal as a quantum object would be nothing less than extraordinary.
So, what did the scientist do to entangle a water bear? They took two electric circuits with two quantum elements capable of mutual connections in a state of entanglement. Then, they placed a water bear that was frozen at -273°C inside one of the circuits of the quantum elements. The presence of the water bear altered the state of the elements which, nevertheless, stayed in a state of entanglement. After that, once the water bear was unfrozen, it resumed its regular life.
However, the experiment also attracted criticism. The main question is: was the water bear fundamental in the system? As much as everybody recognizes the water bears’ extraordinary capabilities and their capacity to survive temperatures nearing absolute zero, many scientists believe that their role within the circuit was not as paramount from a quantum point of view. After all – they say – the same exact outcome could have been obtained with frozen water. In other words, despite the extraordinary performance, the water bear would not add something truly crucial to the system. The study is currently published on arXiv , which collects articles yet to be published in peer-reviewed magazines (officially judged by a group of experts in the sector), and it is for this reason that we can only wait for future developments in this, at the very least, bizarre quantum experiment.