Nobel Prize in Physics: The triumph of quanta

No.Of course, the question of benefit was also raised immediately. And so physics Eva Olsson of Gothenburg’s Chalmers University, as a member of the Nobel Prize Committee, began her summary of her jury’s decision yesterday to award the 2022 Nobel Prize in Physics similarly to Frenchman Alain Aspect. , to American John Clauser and Austrian Anton Zeilinger with relevant keywords: “Quantum information science has potential implications for fields such as secure information transfer, quantum computing and sensor technology.”

Ulf von Rauchhaupt

Publisher in the “Science” section of the Sunday newspaper Frankfurter Allgemeine.

And it is true. In particular, Anton Zeilinger’s lifelong work transformed what seemed an obscure niche of theoretical physics to the general public into a subject with rapidly growing sub-disciplines, some of which are in the process of transforming into engineering sciences. also in view of their practical and commercial promises.

At the heart of all this effort is an effect called “quantum entanglement”. If two things in nature, for the description of which quantum theory is to be used – for example two light photons or subatomic particles – are entangled, then they can only be described together. Therefore nothing can be said about the behavior of one without the other, no matter how distant the two are. Mathematically, this is a consequence and not a postulate of quantum theory. However, one of its pioneers, Zeilinger’s compatriot Erwin Schrödinger, wrote in 1935 that entanglement was not one of the theory’s characteristic properties, but its characteristic.

Making entanglement technically available is the most compelling evidence imaginable of its reality. But this year’s Nobel Prize also recognizes a result that goes much deeper: experimental, and therefore rigorously empirical, physical evidence that quantum theory must itself be correct.

Alain Aspect (* 1947) worked as a teacher in Cameroon for three years before his doctoral thesis.

Alain Aspect (* 1947) worked as a teacher in Cameroon for three years before his doctoral thesis.

Image: AP

John Clauser, (born 1942) turns Einstein's thought experiment into a real attempt.

John Clauser, (born 1942) turns Einstein’s thought experiment into a real attempt.

Image: AP

Forever around 1935 a controversy raged over another property of the new theory, formulated by its founding fathers, including Niels Bohr, Werner Heisenberg, and Max Born, which was actually already in its postulates: it is not deterministic. The only thing that can be derived from quantum laws is the frequency of the different measurement results after repeated measurements. The value of a single measure, on the other hand, is random.

Is quantum theory correct and complete?

It is hardly possible to overestimate the importance of this statement for our understanding of physical reality. She is heartbreaking. Because it says that the decay of a uranium atom, for example, can only be described statistically. Only the probability with which such an atom disintegrated after a given period of time is determined by natural laws. However, it is impossible to calculate in advance when this atom will disintegrate – and thus possibly cause other events, including macroscopic events, such as the outcome of a lottery draw.

If that uranium atom decays, say, one hour after the start of measurement, then there is no reason for this specific event in nature that is scientifically understandable, in contrast to all the processes of classical physics. Newton’s apple falls into the grass after a time that, at least in theory, can be accurately calculated in advance. But quantum things are different. The intuition of the deterministic theory of nature, which had been trained in mechanical processes since the early modern age, no longer applies, or applies only to macrophysics, which forms average values ​​over many atoms. This is actually even more scandalous than the ruin of the intuitions of the Aristotelian theory of nature by Galileo, Kepler and Newton. After all, classical physics still agreed with Aristotle that everything had to have a reason.

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