Читать книгу Quantum Physics is not Weird. On the Contrary. - Paul J. van Leeuwen - Страница 25

Physicists had tried to calculate the theoretical Black Body emission applying classical physics in a similar way as Ludwig Boltzmann ^[17] had successfully done for gases. They combined Boltzmann's statistic methods with Maxwell's laws. To achieve this, they imagined vibrating electrical charges in the inner walls of the Black Body emitter. Based on the Maxwell equations, those vibrating charges should emit and absorb EM radiation in all possible frequencies from infrared to very deep ultraviolet. But according to classical physics theory, an unimaginably huge amount of ultraviolet radiation would be emitted by a white-hot glowing Black Body. The disturbing fact that the classical physics prediction totally derailed in the UV domain - see the rightmost curve in figure 3.12 -challenged physicists like Max Planck to find a better theory.

Planck had, by heuristic trial and error, already found a formula that fitted the measured emission spectra for different temperatures. This success was already very useful, of course, but what he was really searching for was a theory derived from the foundations of physics. He undertook a heroic attempt to derive his heuristic formula from the bottom-up. To that end, he tried - with great reluctance and just as a last resort - to insert in his theory the idea of discrete energy packages of EM radiation that would be emitted and absorbed by the vibrating electrical charges in the walls of the Black Body emitter. He assigned to those discrete energy packages a precise amount of energy proportional to their frequency and named them: quanta. Eureka! His last resort attempt delivered the correct emission prediction and dealt completely with the UV catastrophe. In 1900 Planck published the first quantum theory, 'Zur Theorie der Wärmestrahlung', in the Annalen der Physik ^[18].

Planck confessed later that his idea was born out of an act of desperation. In his desperate attempts, seeking a way out, he assumed that the energy exchange of such an EM quantum - which Albert Einstein later supposed to be a real energy particle - was proportional to the frequency f. Which gives us the formula that every physics student now knows by heart, Planck's Law: E = h.f.

The utterly small value of h - Planck's constant: 6,626 × 10⁻³⁴ Joule seconds - is now engraved on his headstone. With this last-resort daring assumption he was able to derive his equations for the emission of a Black Body emitter completely from basic principles and arrived thus at the perfect prediction for the spectrum of the standard light source. Goal achieved, you would think. But the kinder reactions from his colleague physicists were that it was a nice trick at best, but that his quanta could not have anything to do with physical reality. Such peer responses on a groundbreaking idea are not uncommon in the history of science. In 1918 Planck justly received the Nobel Prize in Physics, 18 years after his publication and only after Einstein had explained the photoelectric effect with Planck's quanta.

Despite this success, Planck, and the later quantum physicists also, were not able to explain how an electromagnetic wave first expands spherically according to Maxwell, its intensity diminishing inversely proportional to the square of the distance to the source, and then changes suddenly into the very local and precise amount of energy transfer represented by the Planck quantum. The question is also, whatever is meant by the frequency of a quantum. This is precisely the problem that the remaining sections of this book will focus on.

Planck himself was at first not really satisfied with his quantum hunch because it clearly could not be reconciled - actually still not - with the wave theories of Huygens, Young and Maxwell, a generally accepted theory at that time. He searched a long time extensively for a "classical" solution, but it evaded him. In the end he radically changed his views on physics, according to his later statements about the relationship between quantum physics and consciousness.

Until then, energy transfer had been considered a continuous phenomenon such as water flowing from a tap. You can fill a container with a thin jet of water slowly, or you can turn the flow up when you are in a hurry. A small, strong jet yields just as much water as a broader but weaker jet. EM radiation behaves entirely different. Consider for example the effect of UV light on your skin. You will never acquire a bronzed skin by sitting patiently in front of a strong infrared source, such as a central heating radiator.

The success of Planck's formula was the beginning of the end of the absolute deterministic view of the world of classical physics. For the infamous demon of Laplace, the past and the future of the universe would be fully determined if classical physics would be right. It is at this moment in history that physics encounters a phenomenon that unquestionably shows that there had to be a false premise, hidden somewhere in her basic assumptions about nature. A paradox emerged, unwilling to leave. The idea of a quantized wave, of discrete packets of EM energy, could in no way be reconciled with Maxwell's EM-wave model. In such a position we have two options:

 we either give up and decide that human imagination simply falls short and that we just have to accept the paradox,

 or we decide to investigate our basic assumptions about reality to establish what could be wrong there.

In the end, Planck proved to be a courageous out-of-the-box thinker. In 1931 he demonstrated this by stating:

"I consider consciousness to be fundamental. I consider matter as derived from consciousness."

We will see later why this is a well-argued position. In my view Max Planck is the icon of the courageous scientist.

 First, he followed his interest in physics going against the common stream.

 Secondly, he was not satisfied with a mathematical expression that accurately predicted the observations but did not reveal its fundaments. He wanted to understand and therefore searched until he had found a way to derive his expression from basic principles. That he had to make uncomfortable assumptions did not stop him. He was willing to put aside his "how-it-is" idea. He ignored his cognitive dissonance.

 Thirdly, because of his courage to come out with a result that would be received in the scientific world with disapproval and rejection. A risky action that seriously could have damaged his career. Just think how long it took for him to be awarded a Nobel prize for physics, 18 years.

Such scientists exist, but they seem to be in a minority.

By the way, Planck only supposed discrete energy transfer between the walls of the Black Body emitter. He did not theorize about speeding light particles (photons) as Einstein would do later in his publication of the photoelectric effect. As you will see later in this book, Einstein's light particles actually lead a very dubious existence.