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Unformatted text preview: arXiv:quantph/0206089v2 30 Jul 2002 Quantum Information and Computation, Vol. 1, No. 0 (2001) 000–000 c circlecopyrt Rinton Press BOOK REVIEW on A New Kind of Science by Stephen Wolfram Wolfram Media, Inc., May 2002 Hardcover $ 44.95 (1192 pages) ISBN: 1579550088 “Somebody says, ‘You know, you people always say that space is continuous. How do you know when you get to a small enough dimension that there really are enough points in between, that it isn’t just a lot of dots separated by little distances?’ Or they say, ‘You know those quantum mechanical amplitudes you told me about, they’re so complicated and absurd, what makes you think those are right? Maybe they aren’t right.’ Such remarks are obvious and are perfectly clear to anybody who is working on this problem. It does not do any good to point this out.” —Richard Feynman [1, p.161] 1. Introduction A New Kind of Science [2], the 1280page treatise by Mathematica creator Stephen Wol fram, has only a few things to say about quantum computing. Yet the book’s goal—to understand nature in computational terms—is one widely shared by the quantum computing community. Thus, many in the field will likely be curious: is this 2.5kilogram tome worth reading? Notwithstanding newspaper comparisons [3] to Darwin’s Origin of Species , what is the book’s actual content? This review will not attempt a chapterbychapter evaluation, but will focus on two areas: computational complexity and fundamental physics. As a popularization, A New Kind of Science is an impressive accomplishment. The book’s main theme is that simple programs can exhibit complex behavior. For example, let p i,j = 1 if cell ( i,j ) is colored black, and p i,j = 0 if white. Then the ‘Rule 110’ cellular automaton is defined by the recurrence p i +1 ,j = p i,j + p i,j +1 − (1 + p i,j 1 ) p i,j p i,j +1 for i ≥ 0, given some initial condition at i = 0. Wolfram emphasizes that such an automa ton, even when run with a simple initial condition such as a single black cell, can generate a complicatedlooking image with no apparent repetitive or nested structure. This phe nomenon, although well known to programming enthusiasts as well as professionals, will no doubt surprise many general readers. 95 96 Book review Using cellular automata as a framework, Wolfram moves on to discuss a range of topics— including the second law of thermodynamics, natural selection, plant and animal morphol ogy, artificial intelligence, fluid dynamics, special and general relativity, quantum mechanics, efficient algorithms and NPcompleteness, heuristic search methods, cryptography and pseu dorandomness, data compression, statistical hypothesis testing, G¨odel’s Theorem, axiomatic set theory, and the ChurchTuring thesis. What is noteworthy is that he explains all of these without using formal notation. To do so, he relies on about 1000 highresolution graph ics, which often (though not always) convey the ideas with as much precision as a formula...
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This note was uploaded on 02/07/2011 for the course PHYS 101 taught by Professor Aster during the Spring '11 term at East Tennessee State University.
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