No one in this world understands what quantum mechanics is. This is perhaps the most important thing you need to know about her. Of course, many physicists have learned to use laws and even predict phenomena based on quantum computation. But it is still unclear why the observer of the experiment determines the behavior of the system and makes it take one of two states.
Here are some examples of experiments with results that will inevitably change under the influence of the observer. They show that quantum mechanics practically deals with the intervention of conscious thought into material reality.
There are many interpretations of quantum mechanics today, but the Copenhagen Interpretation is perhaps the most famous. In the 1920s, its general postulates were formulated by Niels Bohr and Werner Heisenberg.
The Copenhagen interpretation is based on the wave function. It is a mathematical function that contains information about all possible states of a quantum system in which it exists simultaneously. According to the Copenhagen Interpretation, the state of a system and its position relative to other states can only be determined by observation (the wave function is used only to mathematically calculate the probability of finding a system in one state or another).
We can say that after observation, the quantum system becomes classical and immediately ceases to exist in other states than the one in which it was observed. This conclusion found its opponents (remember Einstein's famous "God does not play dice"), but the accuracy of calculations and predictions still had their own.
Nevertheless, the number of supporters of the Copenhagen interpretation is declining, and the main reason for this is the mysterious instantaneous collapse of the wave function during the experiment. Erwin Schrödinger's famous thought experiment with a poor cat should demonstrate the absurdity of this phenomenon. Let's remember the details.
Inside the black box sits a black cat and with it a bottle of poison and a mechanism that can randomly release poison. For example, a radioactive atom can break a bubble during decay. The exact decay time of the atom is unknown. Only the half-life is known, during which decay occurs with a probability of 50%.
Obviously, for an outside observer, the cat inside the box is in two states: it is either alive if everything went well, or dead if the decay has occurred and the bottle has broken. Both of these states are described by the wave function of the cat, which changes over time.
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The more time has passed, the more likely it is that radioactive decay has occurred. But as soon as we open the box, the wave function collapses, and we immediately see the results of this inhuman experiment.
In fact, until the observer opens the box, the cat will endlessly balance between life and death, or will be alive and dead at the same time. Its fate can only be determined by the actions of an observer. This absurdity was pointed out by Schrödinger.
1. Diffraction of electrons
According to a survey of famous physicists by The New York Times, the electron diffraction experiment is one of the most amazing studies in the history of science. What is its nature? There is a source that emits a beam of electrons onto a light-sensitive screen. And there is an obstacle in the way of these electrons, a copper plate with two slits.
What kind of picture can you expect on a screen if electrons are usually presented to us as small charged balls? Two stripes opposite the slots in the copper plate. But in reality, a much more complex pattern of alternating white and black stripes appears on the screen. This is due to the fact that when passing through the slit, electrons begin to behave not only like particles, but also like waves (photons or other light particles behave in the same way, which can be a wave at the same time).
These waves interact in space, colliding and reinforcing each other, and as a result, a complex pattern of alternating light and dark stripes is displayed on the screen. At the same time, the result of this experiment does not change, even if electrons pass one by one - even one particle can be a wave and pass simultaneously through two slits. This postulate was one of the main ones in the Copenhagen interpretation of quantum mechanics, when particles can simultaneously demonstrate their "ordinary" physical properties and exotic properties like a wave.
But what about the observer? It is he who makes this tangled story even more confusing. When physicists during such experiments tried to determine with the help of instruments, through which slit the electron actually passes, the picture on the screen changed dramatically and became "classic": with two illuminated sections strictly opposite the slits, without any alternating stripes.
The electrons seemed reluctant to reveal their wave nature to the watchful eye of observers. It looks like a mystery shrouded in darkness. But there is also a simpler explanation: monitoring the system cannot be carried out without physically influencing it. We will discuss this later.
2. Heated fullerenes
Particle diffraction experiments were carried out not only with electrons, but also with other, much larger objects. For example, they used fullerenes, large and closed molecules consisting of several tens of carbon atoms. Recently, a group of scientists from the University of Vienna, led by Professor Zeilinger, tried to incorporate an element of observation into these experiments. To do this, they irradiated the moving fullerene molecules with laser beams. Then, heated by an external source, the molecules began to glow and inevitably display their presence for the observer.
Along with this innovation, the behavior of molecules has also changed. Before such a comprehensive observation began, fullerenes were quite successful in avoiding the obstacle (exhibiting wave properties), similar to the previous example with electrons hitting the screen. But with the presence of an observer, fullerenes began to behave like completely law-abiding physical particles.
3. Cooling dimension
One of the most famous laws in the world of quantum physics is the Heisenberg uncertainty principle, according to which it is impossible to determine the speed and position of a quantum object at the same time. The more accurately we measure the momentum of a particle, the less accurately we can measure its position. However, in our macroscopic real world, the validity of quantum laws acting on tiny particles usually goes unnoticed.
The recent experiments of Professor Schwab from the USA make a very valuable contribution to this area. Quantum effects in these experiments were demonstrated not at the level of electrons or fullerene molecules (with an approximate diameter of 1 nm), but on larger objects, a tiny aluminum ribbon. This tape was fixed on both sides so that its middle was in a suspended state and could vibrate under external influence. In addition, a device was placed nearby that could accurately record the position of the tape. The experiment revealed several interesting things. Firstly, any measurement related to the position of the object and observation of the tape affected it, after each measurement the position of the tape changed.
The experimenters determined the coordinates of the tape with high precision, and thus, in accordance with the Heisenberg principle, changed its speed, and hence the subsequent position. Secondly, quite unexpectedly, some measurements led to a cooling of the tape. Thus, the observer can change the physical characteristics of objects by his mere presence.
4. Freezing particles
As you know, unstable radioactive particles decay not only in experiments with cats, but also by themselves. Each particle has an average life span, which, as it turns out, can increase under the watchful eye of an observer. This quantum effect was predicted as early as the 1960s, and its brilliant experimental evidence appeared in a paper published by a group led by Nobel Prize-winning physicist Wolfgang Ketterle of MIT.
In this work, the decay of unstable excited rubidium atoms was studied. Immediately after the preparation of the system, the atoms were excited using a laser beam. The observation took place in two modes: continuous (the system was constantly exposed to small light pulses) and pulsed (the system was irradiated with more powerful pulses from time to time).
The results obtained were in full agreement with theoretical predictions. External light effects slow down the decay of particles, returning them to their original state, which is far from the decay state. The magnitude of this effect was also in line with forecasts. The maximum lifetime of unstable excited rubidium atoms increased 30 times.
5. Quantum mechanics and consciousness
Electrons and fullerenes stop showing their wave properties, aluminum plates cool down, and unstable particles slow down their decay. The watchful eye of the beholder literally changes the world. Why can't this be proof of the involvement of our minds in the workings of the world? Perhaps Carl Jung and Wolfgang Pauli (Austrian physicist, Nobel laureate, pioneer of quantum mechanics) were right after all when they said that the laws of physics and consciousness should be seen as complementary to one another?
We are one step away from recognizing that the world around us is just an illusory product of our mind. The idea is scary and tempting. Let's try to turn to physicists again. Especially in recent years, when fewer and fewer people believe the Copenhagen interpretation of quantum mechanics with its cryptic wavefunction collapses, referring to more mundane and reliable decoherence.
The point is that in all these experiments with observations, experimenters inevitably influenced the system. They lit it with a laser and installed measuring devices. They were united by an important principle: you cannot observe a system or measure its properties without interacting with it. Any interaction is a process of modifying properties. Especially when a tiny quantum system is exposed to colossal quantum objects. Some eternally neutral Buddhist observer is impossible in principle. And here the term “decoherence” comes into play, which is irreversible from the thermodynamic point of view: the quantum properties of a system change when interacting with another large system.
During this interaction, the quantum system loses its original properties and becomes classical, as if "obeying" a large system. This also explains the paradox of Schrödinger's cat: the cat is too big a system, so it cannot be isolated from the rest of the world. The very design of this thought experiment is not entirely correct.
In any case, if we assume the reality of the act of creation by consciousness, decoherence seems to be a much more convenient approach. Perhaps even too convenient. With this approach, the entire classical world becomes one big consequence of decoherence. And as the author of one of the most famous books in the field stated, this approach logically leads to statements like "there are no particles in the world" or "there is no time at a fundamental level."
Is it true in a creator-observer or in powerful decoherence? We have to choose between two evils. Nevertheless, scientists are increasingly convinced that quantum effects are a manifestation of our mental processes. And where observation ends and reality begins depends on each of us.
Based on materials from topinfopost.com