Hellaland by Carl Rovelli – a short lesson on quantum physics

Popular books on quantum mechanics almost always amaze and amaze, offering an appealing insight into the deepest mysteries of nature, only to eventually confuse the reader. The greatest popularizer of physics today, Carlo Rovelli, prepares readers of his new book for this famous fate when he warns that if “what I have described seems perfectly clear, then it means that I was not clear enough about it.”

He is too modest. His previous books were intended for readers, including the international phenomenon Seven short physics lessons, set him up as the more literary successor to Stephen Hawking. In Helgoland he sets up his interpretation of the central stage of quantum physics, and the result is a book that allows us to share the almost religious “feeling of Werner Heisenberg“ that I have gone beyond the surface of things. ”as much clarity as possible.

The amazing implications of quantum physics are well known. The properties of objects seem to change depending on whether they are observed or not. Quantum interweaving means that two objects seem to be able to affect each other when they are too far away for any information to reach the other: a photon on Venus could change with a photograph taken in Venice. However, this strange science finds practical use every day, forming the “basis of our latest technologies: from computers to nuclear energy”.

Rovelli finds competing interpretations of quantum theory that aim to solve these puzzles that everyone wants. Therefore, he removes all our assumptions and starts all over again, following the principle “that everything should be based on what we see, and not on what we assume to be the case.” This rigorous empiricism led both Einstein, whose theory of relativity was a forerunner of quantum mechanics, and Heisenberg, one of the early quantum pioneers, who made his early discoveries on the North Sea island of Helgoland.

It sounds obvious, but even many scientists remain attached to metaphysical assumptions that are not based on observation at all. Chief among them is the idea that behind appearance there must be a “well-defined and solid picture of the world” in which objects have inherent and unchanging properties. Science has broken down the world, first into atoms, then into elementary particles, but always assuming that at the bottom there was a reality with a stable, measurable nature.

The pre-democratic philosopher Heraclitus challenged this assumption two and a half millennia ago, postulating a steady world. The Western mind could have taken an entirely different form had his ideas prevailed over the ideas of his successor Plato, who regarded ultimate reality as immutable.

Outside the west, the illusion of strength is less widespread. The richest pre-scientific articulation of the alternative worldview came in the writings of the Indian Mahayana Buddhist thinker Nagarjuna from the second century BC. His doctrine of sunyati or emptiness says that nothing exists entirely for itself, but only in relation to other things. This was not a quantum theory before the letter, but Rovelli argues that Nagarjuna’s middle ground provides the right framework for understanding “a reality that consists of a relationship, not an object.”

Thus, it is not true that quantum theory requires us to accept the absurdity that the properties of objects change depending on whether they are observed or not. Instead, the properties of an object always depend on what it is interacting with. Imagine how the vibration of the air can be invisible to one ear and the unbearable whimpering to the other. Hence, it is not that the view of reality has a special power to change it, but that “any interaction between two physical objects can be considered an observation.”

Quantum entanglement is similarly explained. The moment a third party – in this case, the observer – enters the image, it is not that the image changes but we look at the second image.

The clarity of Rovelli’s exposition would be sufficient for the book to triumph. What elevates him even more is the deep humanity he brings to his subject. For all his immense powers of rationality, this is still a man who always sniffs books before he buys them.

It reminds us that many key players in the development of quantum theory had interests that went far beyond science. Young Heisenberg would memorize Goethe’s poems, “Schrödinger was” fascinated by Asian thoughts “and, like Einstein, was” passionate “about Schopenhauer’s philosophy.”

There is so much in this short but rich book, including a fascinating turn through the dispute between Lenin and his Bolshevik colleague, the polymath Alexander Bogdanov. Rovelli concludes that with all the strangeness of quantum physics, it leaves everything we appreciate not only in place, but also more extraordinary than ever. “Conventional, everyday existence is not denied.”

When the world of permanent objects dissolves, to be replaced by one of processes and interactions, we remain in a world that is not disappointed by science, but even more magical. As Rovelli says: “Precisely because of its impermanence, because of the absence of the absolute, it now has meaning and is precious.”

Helgoland, Carlo Rovelli, Allen Lane, RRP £ 20, 208 pages

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