Something Deeply Hidden: Quantum worlds and the emergence of spacetime
QUANTUM MECHANICS is a fascinating topic that inspires, captivates and bamboozles in equal measure. And as there’s no shortage of explainers for readers of all levels, attempting to write a book on this physics theory is almost as intimidating as the subject itself.
Yet few works carry readers into this complexity as successfully as Something Deeply Hidden. Sean Carroll’s latest work moves from a basic introduction to the field to in-depth discussions of mathematics (such as wave functions and uncertainty principles) and then goes further: grappling with the nature of the quantum realm.
This is ground where few physicists dare to tread, and for good reason: the compellingly articulated theory in this work would see the entire universe “split” in two by simply measureming whether an electron is spinning up or down. Even more incredibly, it makes perfect sense.
Carroll is one of those rare scientists who excels in both science and its communication. His studies are at the forefront of theoretical physics, but he also grapples with concepts of philosophy and more in his Mindcast podcast and Preposterous Universe blog, and through his multiple best-selling books.
This project is particularly close to Carroll’s academic heart, as is the description – and advancement – of Hugh Everett’s description of quantum mechanics: the so-called many-worlds interpretation.
The most direct treatment of quantum mechanics (that a wavefunction traces out – and indeed is – the behaviour of the Universe as a whole) has the astounding consequence that apparently probabilistic outcomes of a measurement are in fact deterministic – but in a different universe.
Going back to our electron, it can be in a quantum state of indecision (known as a superposition), spinning both up and down and not becoming one or the other until it’s measured.
Something Deeply Hidden argues that, rather than some ill-defined and philosophically fraught “observer” reaching down to a somehow separate quantum realm to impact that result, the measurement of an electron as “up” is in the universe you are in now, and “down” in the universe that split from itself just before.
The splitting of universes to form this multiverse occurs in just the right mix as the probabilities that quantum mechanics so uncomfortably appears to present in experiments. Still with me?
What makes this book so impressive is how natural, indeed stunningly logical, such an incredible statement appears. Yet the choice of interpretation is ultimately yours.
Something Deeply Hidden presents the current ideas of quantum mechanics in an entertaining and beautifully explained way, albeit unashamedly favouring the manyworlds interpretation over the rest.
Carroll correctly – and almost as a challenge to the scientific establishment itself – states in the beginning of this engaging book: “As scientists we use quantum mechanics but we don’t understand it.” After reading this we all have a chance.