Quantum tunneling is one of the most interesting things that physicists study …
Imagine a tennis ball hitting a wall. In a situation we are accustomed to, he will bounce off this wall. However, due to the strange nature of the quantum world, there is technically a statistical probability that the ball will end up on the other side of the barrier or even in the wall itself.
Here we are not talking about the fact that the ball will go through the wall, at least, this is not entirely true …
What can happen at the macro level?
If there were a strange case of quantum tunneling at the macro level, then the ball could suddenly disappear when it gets close to the wall, and then immediately reappear on the other side, while the wall itself and the ball would be in their ideal states. Of course, the chances that this will ever happen are extremely small. Nevertheless, there is a statistical probability of this, but in theory it could happen.
The reason for this lies in the probabilistic nature of the quantum world. As proved by Werner Heisenberg's uncertainty principle, the position and momentum of a particle cannot be known simultaneously. For example, if you know the position of an electron, then you cannot know its speed, and if you know the speed, you cannot know its position in space. Because of this, probabilities are used to "guess" where a particle may be at a particular moment in time: an electron may have a high probability of being in one place, and not in another. These probabilities create what is called a "cloud of probabilities."
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Probability Cloud and Quantum Tunneling
As you can see in the figure, the chances of the electron being in the center of the cloud are greater than at the periphery. However, while the odds are incredibly small, there is a statistical chance that an electron could be detected near the edge of the cloud. This is where things start to get weird.
Electron probability cloud.
Quantum tunneling is the ability of a particle, such as an electron, to instantly pass through a barrier. If there is a higher energy barrier than the electron, and the electron approaches it, we usually assume that the electron cannot overcome it. In fact, in most cases it is. Nevertheless, each electron behaves completely unexpectedly from time to time. In rare cases, an electron simply appears on the other side of the barrier.
How is this possible?
Due to the probabilistic nature of electrons, the moment an electron approaches the barrier, there is still a small chance in the probability cloud that the electron could be found on the other side of the barrier.
Probability cloud and barrier.
When this small chance is realized and the electron is on the other side, it means that quantum tunneling has occurred. Technically, the electron does not pass through the barrier, because, oddly enough, at the moment of quantum tunneling, time for the electron does not exist, it happens instantly. In this way, electrons can instantly overcome higher energy barriers.
Stars and quantum tunneling
While this may sound like a very strange and even impossible event, it is actually important to life on Earth as we know it. The sun and all known stars are able to shine through quantum tunneling.
As a result of nuclear fusion, light and heat are released on the sun. Two atomic nuclei, both positively charged, collide to form a new element, and in this process photons are released. The problem, however, is that since both cores are positively charged, they repel each other, just like the same poles of magnets in magnets. This means there is an energy barrier that the nuclei must overcome in order to fuse. However, as mathematics shows, the nuclei on the Sun do not have enough energy to overcome this barrier. The only way to make this possible is through the very rare case of quantum tunneling.
Ironically, quantum tunneling can also have harmful consequences. According to quantum biology, which views living systems from the perspective of quantum theory, DNA mutations can occur in a process called proton tunneling.
If DNA replicates during this quantum tunneling, then mutation can occur. There are other cases of quantum tunneling mutations that some scientists believe cause cancer. There was even an assumption that because of this, living things are aging.
It is strange to think that what allows the Sun to shine and provide life on Earth can also be the reason that everything in nature ages, degrades and dies. However, without quantum tunneling, life as we know it would be impossible.
