One of Smithsonian's Favorite Books of 2018
One of Forbes's 2018 Best Books About Astronomy, Physics and Mathematics
One of Kirkus's Best Books of 2018
The intellectual adventure story of the "double-slit" experiment, showing how a sunbeam split into two paths first challenged our understanding of light and then the nature of reality itself--and continues to almost 200 years later.
Many of science's greatest minds have grappled with the simple yet elusive "double-slit" experiment. Thomas Young devised it in the early 1800s to show that light behaves like a wave, and in doing so opposed Isaac Newton. Nearly a century later, Albert Einstein showed that light comes in quanta, or particles, and the experiment became key to a fierce debate between Einstein and Niels Bohr over the nature of reality. Richard Feynman held that the double slit embodies the central mystery of the quantum world. Decade after decade, hypothesis after hypothesis, scientists have returned to this ingenious experiment to help them answer deeper and deeper questions about the fabric of the universe.
How can a single particle behave both like a particle and a wave? Does a particle exist before we look at it, or does the very act of looking create reality? Are there hidden aspects to reality missing from the orthodox view of quantum physics? Is there a place where the quantum world ends and the familiar classical world of our daily lives begins, and if so, can we find it? And if there's no such place, then does the universe split into two each time a particle goes through the double slit?
With his extraordinarily gifted eloquence, Anil Ananthaswamy travels around the world and through history, down to the smallest scales of physical reality we have yet fathomed. Through Two Doors at Once is the most fantastic voyage you can take.
Science writer Ananthaswamy (The Man Who Wasn't There) guides readers through the odd byways and revelations of one of modern physics's most groundbreaking experiments. The tale begins some 200 years ago when Thomas Young, a youthful member of the Royal Society of London, challenged Isaac Newton's assertion that light is made of tiny particles. Young's experiment shining light through a barrier with two slits cut into it and a screen beyond showed the light beams recombined beyond the slits to create a row of alternating bright and dark stripes, or interference fringes, "created when two waves overlap." But that wasn't the end of the matter, and the particle versus wave question raised new hackles with the early 20th-century breakthroughs of Albert Einstein and the rise of quantum theory. Over the course of this intellectual journey, Ananthaswamy introduces a fascinating array of ideas, e.g., that quantum mechanics means humans should "give up notions of locality in 3-D space our notions of time too," and characters, e.g., "quantum cowboy" Marlan Scully, famed for "pioneering research on the nature of reality and beef cattle production." This accessible, illuminating book shows that no matter how sophisticated the lab setup, the double-slit experiment still challenges physicists.