No one understands what consciousness is and how it works. Nobody understands quantum mechanics. Can this be more than just a coincidence? "I can not determine the real problem, so I suspect that there is no real problem, but I'm not sure that there is no real problem." American physicist Richard Feynman said this about the mysterious paradoxes of quantum mechanics. Today this theory of physics is used to describe the smallest objects in the universe. But in the same way he could tell about the confused problem of consciousness.
Some scientists think that we already understand consciousness or that this is just an illusion. But it seems to many others that we did not even get close to the essence of consciousness at all.
A long-standing puzzle called "consciousness" even led to the fact that some scientists tried to explain it with the help of quantum physics. But their zeal was met with a fair amount of skepticism, and it's not surprising: it seems unreasonable to explain one riddle with the help of another.
But such ideas are never absurd and not even taken from the ceiling.
On the one hand, to the great displeasure of physicists, the mind at first refuses to comprehend the early quantum theory. Moreover, quantum computers are predicted to be capable of such things as ordinary computers can not. This reminds us that our brain is still capable of feats, not available for artificial intelligence. "Quantum consciousness" is widely ridiculed as mystical nonsense, but no one has ever been able to completely dispel it.
Quantum mechanics is the best theory that we have, capable of describing the world at the level of atoms and subatomic particles. Perhaps the most famous of its riddles is the fact that the result of a quantum experiment can vary depending on whether we decide to measure the properties of the particles participating in it or not.
When the pioneers of quantum theory first discovered this "observer effect", they were alarmed in earnest. It seemed that it undermines the assumption underlying the whole of science: that somewhere there exists an objective world independent of us. If the world really behaves depending on how - or if - we look at it, what will "reality" actually mean?
Some scientists were forced to conclude that objectivity is an illusion, and that consciousness should play an active role in quantum theory. Others simply did not see any common sense in this. For example, Albert Einstein was annoyed: does the Moon exist only when you look at it?
Today, some physicists suspect that it's not that consciousness affects quantum mechanics ... but that it has appeared at all, thanks to it. They believe that quantum theory may be needed for us to understand in general how the brain works. Could it be that as quantum objects can be in two places simultaneously, so the quantum brain can simultaneously mean two mutually exclusive things?
These ideas are controversial. It may turn out that quantum physics has nothing to do with the work of consciousness. But they at least demonstrate that strange quantum theory makes us think of strange things.
Best of all quantum mechanics breaks into the human mind through an experiment with a double slit. Imagine a ray of light that falls on a screen with two closely spaced parallel slots. Part of the light passes through the cracks and falls to another screen.
You can imagine the light in the form of a wave. When waves pass through two slits, as in an experiment, they collide-interfere-with each other. If their peaks coincide, they reinforce each other, which translates into a series of black and white bands of light on the second black screen.
This experiment was used to show the wave character of light, more than 200 years, until the quantum theory appeared. Then an experiment with a double slit was performed with quantum particles - electrons. These are tiny charged particles, components of an atom. Unintelligibly, but these particles can behave like waves. That is, they are diffracted when the particle flow passes through two slits, producing an interference pattern.
Now suppose that quantum particles pass through the slots one by one and their arrival on the screen will also be observed step by step. Now there is nothing obvious that would cause the particle to interfere in its path. But the pattern of particle penetration will still show interference fringes.
Everything indicates that each particle simultaneously passes through both slits and interferes with itself. This combination of two paths is known as the state of superposition.
But that's strange.
If we place the detector in one of the slits or behind it, we could find out whether particles pass through it or not. But in this case, the interference disappears. The simple fact of observing the path of a particle - even if this observation does not interfere with the motion of a particle - changes the result.
The physicist Pascual Yordan, who worked with the quantum guru Niels Bohr in Copenhagen in the 1920s, put it this way: "Observations not only violate what needs to be measured, they determine it ... We force a quantum particle to choose a certain position." In other words, Jordan says that "we make the measurements ourselves."
If this is so, the objective reality can simply be thrown out of the window.
But this strangeness does not end there.
If nature changes its behavior depending on whether we look or not, we could try to circle it. For this, we could measure which way the particle chose by passing through a double slit, but only after it passes through it. By that time, she already has to "decide", go through one path or through both.
To conduct such an experiment in the 1970s American physicist John Wheeler suggested, and in the next ten years the experiment with the "deferred choice" was conducted. He uses smart methods to measure the paths of quantum particles (usually light particles - photons) after they choose one path or a superposition of the two.
It turned out that, as Bor predicted, there is no difference whether we detain measurements or not. As long as we measure the path of the photon before it hits and registers in the detector, there is no interference. It seems that nature "knows" not only when we peek, but also when we plan to peek.
Eugene Wigner
Whenever we open the path of a quantum particle in these experiments, its cloud of possible routes is "compressed" into a single well-defined state. Moreover, the delayed experiment assumes that the act of observation itself, without any physical interference caused by measurement, can cause collapse. Does this mean that a true collapse occurs only when the result of the measurement reaches our consciousness?
This possibility was proposed in the 1930s by the Hungarian physicist Eugene Wigner. "It follows that the quantum description of objects is influenced by the impressions that enter my consciousness," he wrote. "Solipsism can be logically consistent with quantum mechanics."
Wheeler was even amused by the idea that the existence of living beings capable of "observing" transformed what was formerly the set of possible quantum pasts into one particular story. In this sense, says Wheeler, we have become participants in the evolution of the universe from the very beginning. According to him, we live in an "associate universe".
Physicists still can not choose a better interpretation of these quantum experiments, and to some extent this right is also granted to you. But, one way or another, the subtext is obvious: consciousness and quantum mechanics are somehow connected.
Beginning in the 1980s, the English physicist Roger Penrose suggested that this connection could work in a different direction. He said that, regardless of whether consciousness affects quantum mechanics or not, it is possible that quantum mechanics participates in consciousness.
Physicist and mathematician Roger Penrose
And Penrose asked: what if in our brain there are molecular structures that can change their state in response to one quantum event? Can these structures assume a state of superposition, like particles in a double-slit experiment? Can these quantum superpositions then manifest themselves in how neurons are communicated by means of electrical signals?
Perhaps, Penrose said, our ability to support seemingly incompatible mental states is not a fad of perception, but a real quantum effect?
After all, the human brain seems to be able to handle cognitive processes, which until now are far superior to digital computers in terms of capabilities. Perhaps we are even able to perform computational tasks that can not be performed on conventional computers using classical digital logic.
Penrose first suggested that quantum effects are present in the human mind, in the 1989 book The Emperor's New Mind. His main idea was "orchestrated objective reduction". Objective reduction, according to Penrose, means that the collapse of quantum interference and superposition is a real physical process, like a bursting bubble.
Orchestrated objective reduction relies on Penrose's assumption that gravity, which affects everyday objects, chairs or planets, does not exhibit quantum effects. Penrose believes that quantum superposition becomes impossible for objects of more atoms, because their gravitational influence in such a case would lead to the existence of two incompatible versions of space-time.
Further, Penrose developed this idea with the American physician Stuart Hameroff. In his book The Shadows of Reason (1994), he suggested that the structures participating in this quantum cognition can be protein strands - microtubules. They are found in most of our cells, including brain neurons. Penrose and Hameroff argued that in the process of oscillation microtubules can take the state of quantum superposition.
But there is nothing to support the fact that it is even possible.
It was suggested that the idea of quantum superpositions in microtubules would support the experiments proposed in 2013, but in fact, these studies did not mention quantum effects. In addition, most researchers believe that the idea of orchestrated objective reductions was debunked by a study published in 2000. The physicist Max Tegmark has calculated that quantum superpositions of molecules involved in neural signals can not survive even the instants of time necessary for signal transmission.
Quantum effects, including superposition, are very fragile and are destroyed in the process of so-called decoherence. This process is due to the interactions of a quantum object with its surrounding medium, since its "quantumness" flows out.
Decoherence was thought to be extremely rapid in warm and humid environments, such as living cells.
Nerve signals are electrical impulses caused by the passage of electrically charged atoms through the walls of nerve cells. If one of these atoms was in a superposition and then collided with a neuron, Tegmark showed that the superposition should disintegrate in less than one billionth of a billionth of a second. To the neuron released a signal, he needs ten thousand trillion times more time.
That's why ideas about quantum effects in the brain are not tested by skeptics.
But Penrose implacably insists on the OOP hypothesis. And despite the prediction of Tegmark's ultrafast decoherence in cells, other scientists have found manifestations of quantum effects in living beings. Some argue that quantum mechanics is used by migratory birds that use magnetic navigation, and green plants when they use sunlight to produce sugar in the process of photosynthesis.
With all this, the idea that the brain can use quantum tricks, refuses to leave for good. Because another argument was found in her favor.
Can phosphorus maintain a quantum state?
In a 2015 study, physicist Matthew Fisher from the University of California at Santa Barbara claimed that the brain could contain molecules capable of withstanding more powerful quantum superpositions. In particular, he believes that the nuclei of phosphorus atoms can have this ability. Phosphorus atoms are found in living cells everywhere. They often take the form of phosphate ions, in which one phosphorus atom is connected to four oxygen atoms.
Such ions are the basic unit of energy in cells. Most of the energy of the cell is stored in ATP molecules that contain a sequence of three phosphate groups linked to an organic molecule. When one of the phosphates is cut off, the energy that is used by the cell is released.
Cells have molecular machines for assembling phosphate ions into groups and for their cleavage. Fischer proposed a scheme in which two phosphate ions can be placed in a superposition of a certain kind: in an entangled state.
The phosphorus nuclei have a quantum property - spin - which makes them look like small magnets with poles pointing in certain directions. In the entangled state, the spin of one phosphorus core depends on the other. In other words, entangled states are states of superposition involving more than one quantum particle.
Fisher says that the quantum-mechanical behavior of these nuclear spins can withstand decoherence. He agrees with Tegmark that the quantum vibrations that Penrose and Hameroff talked about will depend heavily on their surroundings and "decode almost immediately." But the spins of the nuclei do not interact so much with their surroundings.
Nevertheless, the quantum behavior of the spins of the phosphorus nuclei must be "protected" from decoherence.
Quantum particles can have different spins
This can happen, says Fisher, if the phosphorus atoms are included in larger objects, which are called "Posner molecules." They are clusters of six phosphate ions in combination with nine calcium ions. There are definite indications that such molecules can be in living cells, but so far they are not very convincing.
In Posner's molecules, Fisher argues, phosphorus backs can withstand decoherence for a day or so, even in living cells. Therefore, they can affect the brain.
The idea is that Posner molecules can be absorbed by neurons. Once inside, the molecules will activate the signal to another neuron, decaying and releasing calcium ions. Because of the confusion in Posner's molecules, two such signals can be confusing in turn: in some way, it will be a quantum superposition of "thought." "If quantum processing with nuclear spins is actually present in the brain, it would be an extremely common phenomenon that happens all the time," says Fischer.
For the first time this idea came to him when he was thinking about a mental illness.
Lithium Carbonate Capsule
"My introduction to brain biochemistry began when I decided three or four years ago to investigate how and why lithium ion has such a radical effect in treating mental abnormalities," says Fisher.
Lithium drugs are widely used to treat bipolar disorder. They work, but no one really knows why.
"I was not looking for a quantum explanation," says Fisher. But then he came across a work in which it was described that lithium preparations had a different effect on the behavior of rats depending on which form - or "isotope" - lithium was used.
At first this puzzled scientists. From a chemical point of view, the different isotopes behave almost identically, so if lithium worked as a normal drug, the isotopes should have the same effect.
Nerve cells are associated with synapses
But Fisher realized that the nuclei of atoms of different lithium isotopes can have different spins. This quantum property can influence how lithium-based drugs work. For example, if lithium replaces calcium in Posner's molecules, lithium spins can have an effect on phosphorus atoms and prevent their entanglement.
If this is true, it can also explain why lithium can treat bipolar disorder.
At the moment, Fisher's assumption is nothing more than an intriguing idea. But there are several ways to verify it. For example, that the phosphorus spins in Posner molecules can retain quantum coherence for a long time. This is Fisher and plans to check further.
And yet he is afraid to be connected with earlier ideas about the "quantum consciousness", which he considers to be speculative at best.
Consciousness is a profound mystery
Physicists do not like to find themselves within their own theories. Many of them hope that consciousness and the brain can be extracted from quantum theory, and maybe vice versa. But we do not know what consciousness is, let alone that we do not have a theory that describes it.
Более того, изредка звучат громкие возгласы, что квантовая механика позволит нам овладеть телепатией и телекинезом (и хотя где-то на глубине концепций это может быть так, люди понимают все слишком буквально). Поэтому физики вообще опасаются упоминать слова «квантовый» и «сознание» в одном предложении.
В 2016 году Эдриан Кент из Кембриджского университета в Великобритании, один из самых уважаемых «квантовых философов», предположил, что сознание может менять поведение квантовых систем тонким, но вполне обнаружимым образом. Кент очень осторожен в своих высказываниях. «Нет никаких убедительных оснований полагать, что квантовая теория — это подходящая теория, из которой можно извлечь теорию сознания, или что проблемы квантовой теории должны как-то пересекаться с проблемой сознания», признает он.
Но добавляет, что совершенно непонятно, как можно вывести описание сознание, основываясь исключительно на доквантовой физике, как описать все его свойства и черты.
Мы не понимаем, как работают мысли
Один особенно волнующий вопрос — как наш сознательный разум может испытывать уникальные ощущения вроде красного цвета или запаха жарки мяса. Если не считать людей с нарушениями зрения, все мы знаем, на что похож красный, но не можем передать это чувство, а в физике нет ничего, что могло бы нам рассказать, на что это похоже.
Чувства вроде этих называют «квалиа». Мы воспринимаем их как единые свойства внешнего мира, но на деле они являются продуктами нашего сознания — и это трудно объяснить. В 1995 году философ Дэвид Чалмерс назвал это «тяжелой проблемой» сознания.
«Любая мысленная цепочка о связи сознания с физикой приводит к серьезным проблемам», говорит Кент.
Это побудило его предположить, что «мы могли бы добиться некоторого прогресса в понимании проблемы эволюции сознания, если бы допустили (хотя бы просто допустили), что сознание меняет квантовые вероятности».
Другими словами, мозг может действительно влиять на результаты измерений.
С этой точки зрения, он не определяет, «что является реальным». Но он может влиять на вероятность того, что каждая из возможных реальностей, навязанных квантовой механикой, будет наблюдаться. Этого не может предсказать даже сама квантовая теория. И Кент полагает, что мы могли бы поискать такие проявления экспериментально. Даже смело оценивает шансы найти их.
«Я бы предположил с 15-процентной уверенностью, что сознание вызывает отклонения от квантовой теории; и еще 3-процентной — что мы экспериментально подтвердим это в следующие 50 лет», говорит он.
Если это произойдет, мир уже не будет прежним. А ради такого стоит исследовать.
The article is based on materials .
Comments
Post a Comment