The Little Book of String Theory

The Little Book of String Theory

Steven S. Gubser
Copyright Date: 2010
Edition: STU - Student edition
Pages: 184
Stable URL: http:/stable/j.ctt7s7bf
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  • Book Info
    The Little Book of String Theory
    Book Description:

    The Little Book of String Theoryoffers a short, accessible, and entertaining introduction to one of the most talked-about areas of physics today. String theory has been called the "theory of everything." It seeks to describe all the fundamental forces of nature. It encompasses gravity and quantum mechanics in one unifying theory. But it is unproven and fraught with controversy. After reading this book, you'll be able to draw your own conclusions about string theory.

    Steve Gubser begins by explaining Einstein's famous equationE = mc2, quantum mechanics, and black holes. He then gives readers a crash course in string theory and the core ideas behind it. In plain English and with a minimum of mathematics, Gubser covers strings, branes, string dualities, extra dimensions, curved spacetime, quantum fluctuations, symmetry, and supersymmetry. He describes efforts to link string theory to experimental physics and uses analogies that nonscientists can understand. How does Chopin's Fantasie-Impromptu relate to quantum mechanics? What would it be like to fall into a black hole? Why is dancing a waltz similar to contemplating a string duality? Find out in the pages of this book.

    The Little Book of String Theoryis the essential, most up-to-date beginner's guide to this elegant, multidimensional field of physics.

    eISBN: 978-1-4008-3443-3
    Subjects: Physics

Table of Contents

  1. Front Matter
    (pp. [i]-[iv])
  2. Table of Contents
    (pp. [v]-[viii])
    (pp. 1-10)

    String theory is a mystery. It’s supposed to be the theory of everything. But it hasn’t been verified experimentally. And it’s so esoteric. It’s all about extra dimensions, quantum fluctuations, and black holes. How can that be the world? Why can’t everything be simpler?

    String theory is a mystery. Its practitioners (of which I am one) admit they don’t understand the theory. But calculation after calculation yields unexpectedly beautiful, connected results. One gets a sense of inevitability from studying string theory. How can this not be the world? How can such deep truths fail to connect to reality?

    String theory...

  4. Chapter ONE ENERGY
    (pp. 11-18)

    The aim of this chapter is to present the most famous equation of physics:E=mc2. This equation underlies nuclear power and the atom bomb. It says that if you convert one pound of matter entirely into energy, you could keep the lights on in a million American households for a year.E=mc2also underlies much of string theory. In particular, as we’ll discuss in chapter 4, the mass of a vibrating string receives contributions from its vibrational energy.

    What’s strange about the equationE=mc2is that it relates things you usually don’t think of as related.Eis for energy,...

    (pp. 19-33)

    After I got my bachelor’s degree in physics, I spent a year at Cambridge University studying math and physics. Cambridge is a place of green lawns and grey skies, with an immense, historical weight of genteel scholarship. I was a member of St. John’s College, which is about five hundred years old. I particularly remember playing a fine piano located in one of the upper floors of the first court—one of the oldest bits of the college. Among the pieces I played was Chopin’s Fantasie-Impromptu. The main section has a persistent four-against-three cross rhythm. Both hands play in even...

    (pp. 34-48)

    One fine summer day some years ago, I drove with my father up to Grotto Wall, a popular climbing crag near Aspen, Colorado. We aimed to climb a classic moderate route called Twin Cracks. After we finished it without incident, I trotted out another idea: aid-climbing a harder route called Cryogenics. Aid-climbing means putting pieces of hardware into the rock that support your weight, instead of holding on with your hands and feet. You tie yourself to a rope, and you clip the rope to all the hardware you place, so that if the piece you’re standing on pulls out,...

    (pp. 49-68)

    When I was a sophomore at Princeton, I took a course on Roman history. It was mostly about the Roman Republic. It’s fascinating how the Romans combined peaceful and military achievements. They evolved an unwritten constitution and some degree of representative democracy while simultaneously overpowering first their neighbors, then the Italian peninsula, and finally the whole of the Mediterranean and beyond. Equally fascinating is how the civil strife of the late republic ended in the tyranny of the empire.

    Our language and legal system are filled with echoes of ancient Rome. For an example, look no further than the back...

  8. Chapter FIVE BRANES
    (pp. 69-98)

    In 1989, after my junior year in high school, I went to a physics camp. One of the things we did was to hear a lecture on string theory. About halfway through, one of the other students asked a sharp question. He said (more or less), “Why stop with strings? Why not work with sheets, or membranes, or solid three-dimensional chunks of quantum stuff?” The lecturer basically replied that strings seemed to be both difficult enough and powerful enough already, and that they seemed to be special in ways that membranes and solid chunks were not.

    Fast forward about six...

    (pp. 99-116)

    A duality is a statement that two apparently different things are equivalent. I already discussed one example in the introduction: a checkerboard. You can think of it as black squares on a red background, or as red squares on a black background. Those are “dual” descriptions of the same thing. Here’s another example: dancing the waltz. Probably you’ve seen this in old movies, or maybe you’ve even done it. The man and the woman face one another, close together. There’s a particular way you hold your arms, but never mind about that. What matters most is the footwork. When the...

    (pp. 117-139)

    In the summer of 2008, when the construction of the Large Hadron Collider, or LHC, was almost complete, I visited the site and took a tour of one of the main LHC experiments. Mostly I was there for a conference, but the tour was really fun. The experiment I visited, called the Compact Muon Solenoid, is about the size of a three-story building. I saw it in the last stages of being put together. A massive cone-shaped endcap was being fitted into the main barrel-shaped body of the detector. Its design is a little like a digital camera, but every...

    (pp. 140-158)

    A strange fact about the relation between supersymmetry and LHC physics is that the main ingredients were approximately in place twenty years ago or more. There have certainly been advances in the past two decades, both theoretical and experimental. The top quark was a big discovery, although it was long anticipated. The non-discovery of the Higgs constrains models of supersymmetry in interesting ways. Theoretical understanding of supersymmetry has deepened considerably, and the range of possible manifestations of supersymmetry at the LHC has been explored much better than it was in the late 1980s. But these advances have been in some...

    (pp. 159-162)

    There are many aspects of string theory we could ponder after the tour of the subject we have just completed. We could ponder the peculiar demands it seems to make on spacetime, like ten dimensions and supersymmetry. We could ponder the peculiar objects whose existence it requires, everything from D0-branes to end-of-the-world branes. We could ponder its tenuous but improving connection to experimental physics. We could also weigh the controversy that it generates: Is string theory worthwhile? overhyped? Unduly maligned?

    As fascinating as all these topics are, the topic that I think is most worth ending with is the mathematics...

  13. INDEX
    (pp. 163-174)