The tunnel effect is an amazing phenomenon, completely impossible from the standpoint of classical physics. But in a mysterious and mysterious quantum world, slightly different laws of the interaction of matter and energy apply. The tunneling effect is the process of an elementary particle overcoming a potential barrier provided that its energy is less than the height of the barrier. This phenomenon has an exclusively quantum nature and completely contradicts all the laws and dogmas of classical mechanics. The more amazing is the world in which we live.
To understand what a quantum tunneling effect is, it is best possible by the example of a golf ball launched with some force into a hole. At any unit of time, the total energy of the ball is in opposition to the potential force of gravity. If we assume that its kinetic energy is inferior to the force of gravity, then the indicated object will not be able to leave the hole on its own. But this is in accordance with the laws of classical physics. To overcome the edge of the pit and continue on his way, he will definitely need an additional kinetic impulse. So the great Newton spoke.
In the quantum world, things are somewhat different. Now suppose a quantum particle is in the hole. In this case, it will not be a question of a real physical deepening in the earth, but of what physicists conditionally call a “potential hole”. This value also has an analogue of the physical side - the energy barrier. Here the situation is changing in the most dramatic way. For the so-called quantum transition to take place and the particle to be outside the barrier, another condition is necessary.
If the intensity of the external energy field is less than the potential energy of the particle, then it has a real chance to overcome the barrier regardless of its height. Even if she does not have enough kinetic energy in the understanding of Newtonian physics. This is the same tunnel effect. It works as follows. Quantum mechanics is characterized by a description of any particle, not with the help of some physical quantities, but with the help of a wave function related to the probability of a particle being located at a certain point in space in each specific unit of time.
When a particle collides with a certain barrier, using the Schrödinger equation, we can calculate the probability of overcoming this obstacle. Since the barrier not only energetically absorbs the wave function, but also extinguishes it exponentially. In other words, in the quantum world there are no insurmountable obstacles, but there are only additional conditions under which a particle can be beyond these barriers. Various obstacles, of course, interfere with the movement of particles, but by no means are solid impenetrable boundaries. Conditionally speaking, this is a kind of borderline between two worlds - physical and energy.
The tunneling effect has its analogue in nuclear physics - autoionization of an atom in a powerful electric field. Solid state physics is abundant with examples of tunneling. These include field emission, valence electron migration , as well as effects that occur at the contact of two superconductors separated by a thin dielectric film. An exceptional role is played by tunneling in the implementation of numerous chemical processes at low and cryogenic temperatures.