NOf course, the question of the benefit was immediately asked. And so physicist Eva Olsson of Chalmers University in Gothenburg, as a member of the Nobel Prize Committee, began her summary of yesterday’s decision by her panel to award the 2022 Nobel Prize in Physics equally to Frenchman Alain Aspect, American John Clauser. and the Austrian Anton Zeilinger. with relevant keywords: “Quantum information science has potential implications for areas such as secure information transfer, quantum computing and sensor technology.”
And it is true. Anton Zeilinger’s life’s work, in particular, has turned what to the general public seemed an obscure niche of theoretical physics into a subject with rapidly growing subdisciplines, some of which are in the process of morphing into engineering sciences, also given their practical and commercial promises.
At the heart of all these efforts is an effect called “quantum entanglement.” If two things in nature, for the description of which quantum theory is to be used – two photons of light or subatomic particles for example – are entangled, they can only be described together. There is then nothing to say about the behavior of one without the other, no matter how far apart the two are. Mathematically, this is a consequence and not a postulate of quantum theory. However, one of the pioneers, Zeilinger’s compatriot Erwin Schrödinger, wrote in 1935 that entanglement was not one of the characteristic features of the theory, but its hallmark.
Making the entanglement technically available is the most compelling evidence of its reality. But this year’s Nobel Prize also recognizes an achievement that goes much deeper: the experimental physical, and thus strictly empirical, evidence that quantum theory must be correct on its own.
Because also around 1935 a controversy raged about another property of the new theory, as formulated by its founders, including Niels Bohr, Werner Heisenberg and Max Born, which was actually already in her postulates: it is non-deterministic. The only thing that can be deduced from the quantum laws is the frequency of different measurement results after repeated measurements. In contrast, the value of a single measurement is arbitrary.
Is quantum theory correct and complete?
It is hardly possible to overestimate the importance of this explanation for our understanding of physical reality. She is heartbreaking. Because it says that, for example, the decay of a uranium atom can only be described statistically. Only the probability with which such an atom will disintegrate after a certain time is determined by natural laws. However, it’s impossible to calculate in advance when this one atom will disintegrate – and so may cause other events, including macroscopic events, such as the outcome of a lottery.
If that uranium atom decays, say, an hour after the start of the measurement, then there is no scientifically intelligible reason for this particular event – unlike all the processes of classical physics. Newton’s apple falls to the grass after a time which, at least theoretically, can be precisely 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 period, no longer applies, or only applies in macrophysics, which forms average values over many atoms. This is actually more scandalous than the demise of the intuitions of the Aristotelian theory of nature caused by Galileo, Kepler and Newton. After all, classical physics still agreed with Aristotle that everything must have a reason.