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the Complete Review
the complete review - science / history


Through Two Doors at Once

Anil Ananthaswamy

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To purchase Through Two Doors at Once

Title: Through Two Doors at Once
Author: Anil Ananthaswamy
Genre: Non-fiction
Written: 2018
Length: 266 pages
Availability: Through Two Doors at Once - US
Through Two Doors at Once - UK
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Through Two Doors at Once - India
  • The Elegant Experiment That Captures the Enigma of Our Quantum Reality

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Our Assessment:

B : interesting approach; works quite well

See our review for fuller assessment.

Review Summaries
Source Rating Date Reviewer
Nature . 7/8/2018 Philip Ball
Wall St. Journal . 3/8/2018 Andrew Crumey
The Washington Post . 9/8/2018 Margaret Wertheim

  From the Reviews:
  • "Ananthaswamy offers some of the most lucid explanations I’ve seen of other interpretations. (...) Refracting all of quantum mechanics through the double slits is both a strength and a weakness of Through Two Doors at Once. It brings unity to a knotty subject, but downplays some important strands." - Philip Ball, Nature

  • "Mr. Ananthaswamy interviewed many leading theoreticians and experimentalists in the course of writing this book, and he covers a large and complex field in an admirably accessible way. Historical or biographical details are mostly subordinated to scientific and philosophical issues, though we glimpse a few colorful characters." - Andrew Crumey, Wall Street Journal

  • "At a time when popular physics writing so valorizes theory, a quietly welcome strength of Ananthaswamy’s book is how much human construction comes into focus here. This is not "nature" showing us, but us pressing "nature" for answers to our increasingly obsessional questions." - Margaret Wertheim, The Washington Post

Please note that these ratings solely represent the complete review's biased interpretation and subjective opinion of the actual reviews and do not claim to accurately reflect or represent the views of the reviewers. Similarly the illustrative quotes chosen here are merely those the complete review subjectively believes represent the tenor and judgment of the review as a whole. We acknowledge (and remind and warn you) that they may, in fact, be entirely unrepresentative of the actual reviews by any other measure.

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The complete review's Review:

       Through Two Doors at Once is, as Anil Ananthaswamy explains: "the story of quantum mechanics from the perspective of one classical experiment and its subtle, sophisticated variations". The experiment is generally known as the 'double-slit experiment', first made famous by the great Thomas Young, which shows an interference pattern when light is passed through two side-by-side slits -- apparent proof that light is a wave. Ananthaswamy doesn't focus so much on the original experiment(s) but rather on those later (many, and often ingenious) variations -- because, as it turns out, the basic experiment -- 'particles' sent through one and two slits, and what results (as they behave under some circumstances like we expect particles would, under others like waves) -- can provide further insight into the most fundamental physics (yes, the quantum stuff). It's an interesting approach, and it works quite well.
       While the Copenhagen interpretation quickly established itself as the (almost completely) dominant view of quantum mechanics, many scientists -- most notably Einstein -- have continued to had issues with it. Bell's theorem and Bohmian mechanics address some of these -- and have proven to be fruitful avenues (among others) by which to explore the nature of quantum mechanics. Ananthaswamy leads readers through the thought- and then also practical experiments that have been developed to further examine it -- an often fascinating account of both the theoretical and experimental advances that have been made, especially in recent times.
       Among the difficulties of working on this small scale is simply how to 'measure' results (as, on that scale, measurement itself interferes with the experiment), and Ananthaswamy usefully follows how technological and experimental advances, and different approaches (such as "interaction-free experiments") have made possible experimentation at remarkable levels -- down to passing single photons through a slit.
       The necessary tweaks and what has to be taken into account are often quite fascinating, from trying to find (or make) molecules of larger and larger size, to see up to what size there is interference, to how to build a set-up that allows for taking the effects of gravity into account (necessary when particles travel larger distances). Among the neat little observations is how when Anton Zeilinger's team did their delayed-choice quantum eraser experiment between La Palma and Tenerife ("144 kilometers away as the crow -- or in this case, the photon -- flies"):

Near complete darkness was essential. Once, one of Ursin's colleagues stood near the source, smoking a cigarette. The infrared photons from the glowing cigarette at La Palma completely saturated the receiver on Tenerife, overwhelming the signal of the lone environment photon.
       Ananthaswamy's book focuses on the theories (and the experiments behind them), but also covers the personalities involved, including some historical detail and anecdotes as well as in brief personal encounters with major players in the field -- Alain Aspect, Roger Penrose, Zeilinger, among many others. The personal touch offers bits and pieces of interest too, but can feel a bit like journalistic anecdotage (since Ananthaswamy doesn't have (or take) the space to really go in-depth with these scientists) -- a familiar trend in contemporary science books. Certainly, limiting discussion to the theory and experiments and leaving the personalities (or at least the personal encounters) out of it would have been fine; as is, they are a bit distracting.
       Covering the major interpretations and theories of quantum mechanics -- including QBism and many-worlds-theories --, and nicely showing the place and use of variations of the double-slit experiment in considering and evaluating all of these, Ananthaswamy manages to give a good overview of 'the enigma of our quantum reality'. It is a fairly brisk tour, but his approach makes for a good and reasonably thorough overview.

- M.A.Orthofer, 23 August 2018

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Through Two Doors at Once: Reviews: Anil Ananthaswamy: Other books of interest under review:

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About the Author:

       Anil Ananthaswamy is an author and journalist.

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© 2018 the complete review

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