There is a hypothesis, more precisely a set of hypotheses, according to which our brain is nothing more than a biochemical quantum computer. These ideas are based on the assumption that consciousness is inexplicable at the level of classical mechanics and can be explained only with the use of postulates of quantum mechanics, superposition phenomena, quantum entanglement and others. Scientists from the University of California at Santa Barbara decided, through a series of experiments, to find out whether our brain really is a quantum computer.
At first glance, it might seem that the computer and the brain work in the same way – both process information, can store it, make decisions, and also deal with input and output interfaces. In the case of the brain, these interfaces are our senses, as well as the ability to control various objects that are not part of our body, for example, artificial prostheses.
We do not know much about how our brain works. But there are people who believe that the variety of processes in our brain that can not be explained from the point of view of classical mechanics can be explained from the position of quantum mechanics. In other words, they are sure that such aspects of quantum mechanics as quantum entanglement, superposition phenomenon and all the other things that quantum physics works on can in fact control the processes of our brain. Of course, not everyone agrees with this formulation, but somehow the scientists decided to test it.
"If the question of quantum processes occurring in the brain finds a positive response, this will lead to a real revolution in our understanding and treatment of brain functions and cognitive abilities of a person, "says Matt Helgeson of the University of California at Santa Barbara and one of the team members involved in the study.
A little basic theory. In the world of quantum computing, everything is subject to quantum mechanics, which makes it possible to explain the behavior and interaction of the tiniest objects in the universe – at the quantum level, where the rules of classical physics do not work. One of the key features of quantum computing is the use of so-called qubits (quantum bits) as an information carrier. Unlike regular bits that are used in ordinary computers and represent a binary code in the form of "zeros" and "ones", the qubits can simultaneously acquire values of both zero and unit, that is, in the so-called superposition, which was mentioned above.  If we proceed from the above, quantum computers promise simply incredible potential in computer calculations, which will allow us to cope with tasks (including in science), which even the most powerful but ordinary computers can not.
As for a new study of scientists from the University of California, which is about to begin, it will be aimed at finding "brain qubits."
One of the main features of "ordinary" qubits is that they require a medium with a very low temperature approaching absolute zero, but researchers suggest that this rule may not extend to qubits that may be in the human body.
In the framework of one of the upcoming experiments, scientists will try to find out whether it is possible to store qubits inside the spin of the atomic nucleus, and not among the electrons that surround it. In particular, the atoms of phosphorus, the substance contained in our organisms, should be the object of research, according to scientists who are able to play the role of biochemical qubits.
"Carefully isolated nuclear spins can store and possibly process quantum information for hours or even more time, "says one of the study participants, Matthew Fisher.
In the context of other experiments, scientists want to look at the potential of decoherence, which occurs as a result of breaking the bonds between the qubits. During the course of this process, classical features begin to appear in the quantum system itself, which correspond to the information available in the environment. In other words, the quantum system begins to mix or become entangled with the environment. In order for our brain to be regarded as a quantum computer, it must have a system that would protect our biological qubits from this decoherence.
The task of another experiment will be the study of mitochondria, the cellular subunits responsible for our metabolism and transmission energy within our body. Scientists suggest that these organelles can play a significant role in quantum entanglement and have a quantum bond with neurons.
In general, neurotransmitters (the active chemical substances that transfer electrochemical impulses) between neurons and synaptic connections may create in our brain integrated quantum networks. Fisher and his team want to test this by attempting to reproduce such a system in the laboratory.
The processes of quantum computing, if they are actually present in our brain, will help us explain and understand the most enigmatic of its functions, for example, its ability to transfer memory from short-term to long-term, or to get close to understanding the questions about where our consciousness, awareness and emotions really come from.
All this is a very high level, very complex physics, along with biochemistry, so here it will not guarantee that we will be able to get all the answers to the above questions. Even if it turns out that we have not yet reached the necessary level that would allow us to answer the question of whether our brain is a quantum computer, the planned studies can make a great contribution to understanding how the most complex human organ works.