Three Roads To Quantum Gravity (Science Masters) [Paperback]

Lee Smolin (Author)

Book Description

Publication Date: July 4, 2002 | ISBN-10: 0465078362 | ISBN-13: 978-0465078363 | Edition: Reprint

The Holy Grail of modern physics is a theory of the universe that unites two seemingly opposing pillars of modern science: Einstein's theory of general relativity, which deals with large-scale phenomena (planets, solar systems and galaxies), and quantum theory, which deals with the world of the very small (molecules, atoms, electrons). In Three Roads to Quantum Gravity, Lee Smolin provides the first concise and accessible overview of current attempts to reconcile these two theories in a final "theory of everything." This is the closest anyone has ever come to devising a completely new theory of space, time and the universe to replace the Newtonian ideas that were the foundation of all science until the beginning of the twentieth century. Lee Smolin, who has spent his career at the forefront of these new discoveries, presents for the first time the main ideas behind the new developments that have brought a quantum theory of gravity in sight. He explains in simple terms what scientists are talking about when they say the world is made from exotic entities such as loops, strings, and black holes. As he does so, he tells the fascinating stories behind these discoveries: the rivalries, epiphanies, and intrigues he witnessed firsthand.Science Masters Series

Editorial Reviews

Amazon.com Review

It's difficult, writes Lee Smolin in this lucid overview of modern physics, to talk meaningfully about the big questions of space and time, given the limitations of our technology and perceptions.

It's more difficult still given some of the contradictions and inconsistencies that obtain between quantum theory, which "was invented to explain why atoms are stable and do not instantly fall apart" but has little to say about space and time, and general relatively theory, which has everything to say about the big picture but tends to collapse when describing the behavior of atoms and their even smaller constituents. Whence the hero of Smolin's tale, the as-yet-incomplete quantum theory of gravity, which seeks to unify relativity and quantum theory--and, in the bargain, to move toward a "grand theory of everything." Smolin ably explains concepts that underlie quantum gravity, such as background independence, the superposition principle, and the notion of causal structure, and he traces the development of allied theories that have shaped modern physics and led to this new view of the universe.

Although he allows that "it has not been possible to test any of our new theories of quantum gravity experimentally," Smolin predicts that a solid framework will be established by 2015 at the outside. If he's correct, the years in between promise to be an exciting time for students of the physical sciences, and Smolin's book makes an engaging introduction to some of the big questions they'll be asking. --Gregory McNamee --This text refers to an out of print or unavailable edition of this title.

From Publishers Weekly

The most obvious questions--e.g., "What are time and space?"--are nearly impossible to answer. Smolin (The Life of the Cosmos), professor of physics at Pennsylvania State University, offers "a report from the front" of the current "revolution" in theories of space and time. Aimed at beginners, this careful treatment of the search for a single theory that brings together relativity and quantum theory will draw in potential explorers. Illus.

Copyright 2001 Cahners Business Information, Inc.

--This text refers to an out of print or unavailable edition of this title.

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Product Details

• Paperback: 256 pages
• Publisher: Basic Books; Reprint edition (July 4, 2002)
• Language: English
• ISBN-10: 0465078362
• ISBN-13: 978-0465078363
• Product Dimensions: 5.3 x 0.7 x 8 inches
• Shipping Weight: 14.1 ounces (View shipping rates and policies)
• Average Customer Review: 4.0 out of 5 stars  See all reviews (53 customer reviews)
• Amazon Best Sellers Rank: #265,023 in Books (See Top 100 in Books)

More About the Author

Lee Smolin earned his Ph.D. in physics at Harvard, then went on to teach at Yale and Pennsylvania State before helping to found the innovative Perimeter Institute. He is the author of The Life of the Cosmos and Three Roads to Quantum Gravity.

Most Helpful Customer Reviews

117 of 122 people found the following review helpful

4.0 out of 5 stars Readers get at least a vague picture of a difficult problem July 27, 2001

By Tatsuo Tabata

Format:Hardcover

The completion of a quantum theory of gravity (quantum gravity for short) is one of the most challenging problems in science in the twenty-first century. This theory aims at unifying Einstein's theory of general relativity for large-scale phenomena with the quantum theory for the micro-world, to get understanding of everything from space and time to matter and the universe. Lee Smolin, Professor of Physics at Pennsylvania State University, tells the story of recent and future research pursuing this theory for the intelligent layperson.

The author writes earlier chapters very understandably. The reader who knew nothing about the quantum gravity learns easily the following interesting things: There are three approaches to quantum gravity, i.e., the route from quantum theory (string theory), the road from the theory of general relativity (loop quantum gravity), and the path from fundamental principles. To do cosmology the classical logic demanding that every statement be either true or false is inadequate. A theory of quantum gravity has to answer about the nature of the information tapped in a quantum black hole. The search for the meaning of the temperature and entropy of a black hole is now leading to the discovery of the atomic structure of space and time. Etc.

In the middle of the book the author states that the style of these chapters will be more narrative than others because he can describe from personal experience some of the episodes in the development of loop quantum gravity. Lessons told are, for example, as follows: Science progresses quickly when people with different backgrounds and educations join forces. Einstein's example teach us that trying to invent new laws of physics requires not only intelligence and hard work but also insight, stubbornness, patience and character. Of course, these are also quite understandable.

In the last three chapters some or most of readers might find it difficult to follow the author's explanation. After reading the whole book, however, all the readers would feel that they have gotten at least a vague picture about the difficult problem of proceeding to quantum gravity. This is an exciting book for those who want to catch a glimpse of theoretical physics at its forefront.

There are some typos. Among them the followings are especially unfortunate, because the meanings of one of the laws of thermodynamics and the Heisenberg uncertainty principle are completely reversed to lead laypersons astray: In chapter 7, "The second law of thermodynamics requires only that the total entropy of the world never increase" should read "The second law . . . never decreases." In two inequalities in chapter 11, the symbol of "less than" should be that of "greater than or equal to."

52 of 54 people found the following review helpful

3.0 out of 5 stars Nice book on Quantum Gravity July 19, 2001

By K. Graham

Format:Hardcover|Amazon Verified Purchase

I approached this book with great enthusiasm, hoping for a pedestrian treatment of loop quantum gravity (LQG). To be fair, most of this book is pretty good. Smolin writes pretty well, especially about relational quantum mechanics and how it relates to quantum gravity and cosmology. In addition, Smolin clearly points out why many relativists have issue with string/m-theory's lack of background independence.

I was, however, mildly disappointed in his discussion of the physical meaning of spin networks and loops and in his exposition of a possible synthesis of M-theory and LQG. Perhaps I overlooked it, but this book doesn't directly point out how you go from spin networks and spin foams to spacetime. But, you can figure it out... if you know enough general relativity and quantum field theory.

The appendix of this book is excellent! It provides many useful references to the literature.

All things considered though, this book is worth a read, especially to learn about the connection between spacetime, gravity, and quantum mechanics.

I originally rated this three stars. I recently reread the book and now want to give it four stars.

23 of 23 people found the following review helpful

4.0 out of 5 stars Very good, but no audience is ideally served June 4, 2006

By Irfan A. Alvi TOP 1000 REVIEWERVINE™ VOICE

Format:Paperback

As my title states, this book is very good, but with the significant caveat that no particular audience is ideally served by it.

If you are truly a layman, you may initially be pleased to find that the book has essentially no formal mathematics and the technical vocabulary isn't too extensive. Smolin himself says that the book is aimed at the "intelligent layman" and that "the reader who has not read anything previously on these subjects will be able to follow this book." However, the book tries to convey a meaningful understanding of some rather advanced (some would say speculative) physics in the areas of thermodynamics of black holes, loop quantum gravity, and string theory, and it does this in a manner which is philosophically sophisticated, with many fundamental questions being raised about the nature of space, time, and scientific theories in general. Moreover, despite Smolin's claim to the contrary, one can't adequately appreciate what the book is about without a basic (at least popular-level) background in quantum mechanics and relativity, which the book doesn't provide.

As a result, I anticipate that the true layman would find this book to be difficult going. Instead, a more realistic audience would be the "advanced layman" who has some prior familiarity with this subject matter, particularly the basics of quantum theory, relativity, the standard model, and cosmology. This audience (which includes me) would probably find the book to be quite stimulating and interesting, and would get a sense of what this advanced physics is all about. However, because the presentation lacks the mathematics and technical details needed for anything resembling a rigorous understanding, they will probably also be left wishing the book had 50 more pages of "meat" and some key equations (explained carefully, but without derivations). For the same reason, the advanced reader would probably also wish the book was at least one notch more advanced, but even these readers may still find the book to be a fun and interesting overview of the subject.

Finally, I'd like to suggest that potential readers should be wary of reviewers who strongly favor the book because they agree with it's thesis, or condemn the book because they disagree. We are dealing with subject matter about which there is no consensus even among eminent physicists, so these reviews are not the place for readers to throw in their two cents about which theories are right and wrong. Instead, this sort of book should be judged mainly on criteria such as whether good questions are asked, whether the context for these questions is well formed, whether the alternative answers proposed for these questions are explained clearly and fairly, and whether the text is well-written. On all of these counts, my judgement is that Smolin does a good job.