Something Deeply Hidden

July 1, 2019
Theoretical physicist Carroll (The Big Picture) explores holes in the foundation of modern physics in this challenging, provocative book. Quantum mechanics is, according to Carroll, “the deepest, most comprehensive view of reality we know of.” But while it answers questions about how the universe works at the microscopic level, quantum theory still, nearly 100 years after its introduction, has unresolved issues. Albert Einstein disdained quantum mechanics as “spooky” and said it would never be complete, and so far, Carroll says, he’s been right. Carroll presents his argument with words rather than math, striving to make even the most abstract ideas clear. At the heart of his discussion are equations called “wave functions” that describe the real world. The problem is that wave functions have many possible solutions and each describes a branch, or another reality, in spacetime. Carroll gives a sense of both the frustration and the wonder that the many-worlds theory inspires, and what it implies about free will and human consciousness. Moving smoothly through different topics and from objects as small as particles to those as enormous as black holes, Carroll’s exploration of quantum theory introduces readers to some of the most groundbreaking ideas in physics today. (Sept.) This review has been updated with more precise language regarding wave functions.

July 1, 2019
The latest attempt to describe the "holy grail of modern physics." Although in theory it works brilliantly, no one fully understands quantum mechanics. However, Carroll (Theoretical Physics/Caltech; The Big Picture: On the Origins of Life, Meaning, and the Universe Itself, 2016, etc.) works hard--and somewhat successfully--to deliver an accessible explanation. "Quantum mechanics," he writes, "is unique among physical theories in drawing an apparent distinction between what we see and what really is....If we free our minds from certain old-fashioned and intuitive ways of thinking, we find that quantum mechanics isn't hopelessly mystical or inexplicable. It's just physics." This doesn't bother most physicists, who belong to the shut-up-and-calculate school, and searching for a deep meaning is unfashionable. Carroll swims against the tide, explaining several theories that attempt to describe what is happening, with an emphasis on his favorite, the many-worlds theory. He begins by pointing out that in our everyday world, the world of classical mechanics, every object has two features: a location and a velocity. Everything is transparent; whatever happens to that object is explained by classical laws of physics--essentially Newton's. In contrast, every quantum object has one feature: a wave function defined by Schrödinger's 1926 equation, which explains what happens when one measures it. Although true for objects of any size, quantum mechanics becomes essential at the atomic and subatomic levels. Some popular writers proclaim that this demonstrates our ignorance or perhaps a mysterious spiritual element in the universe. The author disagrees but admits that, as a description of how reality works, it makes no sense. Eschewing mathematics, Carroll labors mightily to reveal the meaning behind quantum mechanics with a major detour into general relativity, both of which might benefit from at least a little math. Readers who remember freshman college physics will be intrigued; others will struggle.

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Starred review from August 1, 2019
Armchair physicists everywhere know how Niels Bohr bested Albert Einstein in their clash over quantum mechanics. But Carroll convincingly shows that Bohr prevailed by offering powerful formulas while dodging the questions Einstein raised about the fundamental realities behind those formulas. Readers revisit these questions by pondering the puzzling consequences of any measurement in Bohr's quantum system and considering the baffling failure of that system to explain the dynamics of quantum phenomena. Laying aside Bohr's mystifications, Carroll finds a rigorous response to Einstein's concerns in the quantum theorizing of Hugh Everett III. Readers will recognize the attractiveness of Everett's quantum paradigm, offering a clear picture of reality, not merely a blur of probabilities. They will appreciate, too, the conceptual parsimony of a quantum science distilling its entire framework in a single wave formula. But they must confront the paradigm's controversial implication that every quantum event spawns a new, parallel universe. Though many physicists resist Everett's notion of physically unobservable universes, Carroll argues persuasively that every available alternative to Everett's formulation entangles scientists in inconsistencies likely to foreclose progress in developing a much-needed quantum explanation of gravity. Readers in this universe (and others?) will relish the opportunity to explore the frontiers of science in the company of titans.(Reprinted with permission of Booklist, copyright 2019, American Library Association.)

August 1, 2019

Caltech theoretical physicist Carroll (The Big Picture) wants readers to know that the current understanding of reality is wrong, arguing that the Multi Worlds theory related to quantum reality is the correct view to perceive the universe. The author begins with a statement that many physicists believe they fully understand the universe based on ideas developed in 1927, but that they only understand a piece of the bigger picture. After a brief historical overview of the development of quantum physics, Carroll spends the remainder of the book explaining that every time an event is observed, reality splits into different branches. This is ultimately the Multi Worlds idea: that each observation or event causes a duplicate reality to form where that observation or event did not occur. Carroll uses some equations to prove his concepts and describes them clearly. Readers unfamiliar with quantum physics may have difficulty grasping the concepts, but after some rereading of more advanced ideas (such as the wave function), they should begin to understand the hypotheses provided. VERDICT Fans of popular science authors such as Neil deGrasse Tyson and John Gribbin will find great joy while exploring these groundbreaking concepts. [See Prepub Alert, 3/4/19.]--Jason L. Steagall, formerly with Gateway Technical Coll. Lib., Elkhorn, WI

Copyright 2019 Library Journal, LLC Used with permission.

August 1, 2019

Physics is in crisis regarding quantum mechanics, which has led to a Many Worlds theory positing that with every quantum event a parallel world is spun off, giving us a multiplicity of universes. Carroll argues for accepting that seemingly unimaginable outcome and getting on with it: Einstein's general theory of relativity, which we've been trying to reconcile with quantum mechanics, emerges with the concept of gravity from a deeper reality called the wave function we should really be pondering. From New York Times best-selling Caltech physicist Carroll (The Particle at the End of the Universe).

Copyright 2019 Library Journal, LLC Used with permission.