How can absolute emptiness be a source of limitless energy? Understanding the concept of zero point

Remember the phrase of Friedrich Nietzsche “When you peer into an abyss for a long time, the abyss begins to peer into you”? This quote best describes the subject of this discussion. But let's start, as usual, from afar.

Imagine a heated block or stone. It consists of particles that constantly move in space. According to the basics of molecular kinetic theory, the measure of motion of these particles is described by temperature. The specific values ​​of this temperature determine the thermal energy of the system. Based on the classical (we will use the word “classical” for standard concepts from a school physics textbook) theory, a state is possible in which absolute rest occurs at zero temperature on the Kelvin scale. All particles freeze and stop moving. Thermal processes stop completely. At the same time the energy of such a system is also zero.

Theoretically, a state is possible when the classical system (our long-suffering block or stone) will have zero energy. In simple terms, this is complete absence energy. Now let's get to the fun part. How are things going in quantum systems?

There is such an incredibly interesting concept in this area as zero point energy. And, looking ahead, I will say that in essence this is the energy of absolute emptiness, from which it is even possible to “generate” new particles.

Zero point energy refers to the minimum possible energy that a quantum mechanical system can have, even when it is in its ground state (the state with minimum energy).

Unlike classical systems (like our example bar), where a system at zero temperature would have zero energy, quantum systems still have some residual energy due to the inherent uncertainty of quantum mechanics.

This energy is often called quantum fluctuations or vacuum energy and has many interesting concepts, theories and hypotheses associated with it.

Where did the zero point come from?

In quantum mechanics, Heisenberg's uncertainty principle states that we can never know with absolute accuracy both the position and momentum of a particle. This means that even in a vacuum (space without matter), particles and fields still experience energy fluctuations (any random deviation of any quantity is called a fluctuation). Essentially this one of the explanations for the nature of the existence of the zero point.

Since everything is uncertain, we cannot talk about a “stable” or classical state of a particle. Here the idea intersects with the idea that particles are the result of vacuum fluctuations, and therefore the vacuum will never be empty. Hence, if in a vacuum there is a field, whatever it may be, then this field, even without the generation of a specific particle, can vibrate arbitrarily (even without the generation of new particles) and this is its main property.

Fluctuations can lead to the short-term appearance and disappearance of so-called virtual particles. These particles appear and disappear, borrowing energy from the vacuum and then returning it within a short time, as allowed by quantum rules. Moreover, virtual particles, under certain conditions, are capable of generating quite real particles. For example, think about the birth of couples. So much for the energy of emptiness.

The vacuum of space is not actually empty, but is filled with fluctuating fields and particles. The energy of these fluctuations is called vacuum energy or zero point energy. And you probably remember about the not entirely clear cosmological constant. I did a short video on this topicwhich was criticized in many ways correctly, but did not catch the main idea of ​​​​the story. The point was to describe the strange logic of the appearance of many constants.

Einstein, while working on the general theory of relativity, established that “it does not dance.” If a vacuum has no energy, then how will the Universe expand? Therefore, a certain value was introduced into the calculation system that evens out this discrepancy. She was named cosmological constant and its origin has long occupied the minds of physicists. Studying the issue sometimes led to funny situations, as was the case with Eddington. It would be worth telling about this funny incident separately, but let us briefly recall the essence of the problem. I may be confusing the sequence and specific facts here, but the main thing is to realize the comical nature of the situation.

Eddington pulled one value after another and said, pleased, that he had found an explanation for the specific value of the cosmological constant. A group of young physicists repeated this trick and based some strange relationship of unrelated physical constants in some new research using Eddington's results. Things got to the point that the article published by the guys was almost nominated for a Nobel Prize. They had to intervene in the long-running joke and the authors were asked to retract the joke article. Eddington later did the same, admitting that he was not objective. But let's return to the main question.

Vacuum energy can precisely be the source of the cosmological constant, which Einstein introduced in the equations of general relativity. The cosmological constant is sometimes seen as a form of dark energy responsible for the accelerating expansion of the Universe.

Is it true that vacuum energy can be “touched”?

The reader usually has a traditional question: how can you touch and see all this? In the case of the zero point, everything is quite interesting. There is a well-known indirect effect that can demonstrate the existence of zero energy point or energy of absolute vacuum.

Have you heard about the Casimir effect? When two uncharged parallel metal plates are placed very close to each other in a vacuum, they experience an attractive force due to quantum fluctuations in the electromagnetic field between them. This experiment demonstrates that the vacuum is not empty, but at the same time suggests that it has energy.

Quantum fluctuations in a vacuum exert pressure on the plates. Because certain wavelengths of virtual particles are excluded between the plates (due to the small gap), the pressure outside the plates is greater than between them, resulting in a force that pushes the plates towards each other.

What is the value of the zero point?

The zero point concept has a hypothetical application. Moreover, thanks to this, it is possible to explain such complex phenomena as the birth of pairs or even the spontaneous appearance of particles.

Some speculative ideas suggest the possibility of harnessing zero point energy as a nearly limitless source of energy. However, this is still a hypothesis and the logic is more like science fiction.

If zero-point energy truly exists at every point in the vacuum, its cumulative effect could have a large impact on the geometry of spacetime, as described in Einstein's general theory of relativity. Moreover, given that zero-point energy can theoretically have a repulsive effect, it could be related to the phenomenon of cosmic inflation (the rapid expansion of the early Universe) or the current accelerated expansion attributed to dark energy.

This is an incredibly interesting concept. As usual, it is difficult to explain and breaks our usual logic. But at the same time, given the real existence of such a phenomenon, this will explain a lot. And the very fact that nothing has energy is very impressive.

As usual, I invite all lovers of physical knowledge to the Telegram channel of my project.