No new theory can develop without dedicated scientists working hard to refine and interpret it. Throughout this book, you read about some of the pioneering work in string theory. Now it’s time to find out more about some of the scientists themselves, the people who make string theory tick as they research the mysteries of the universe within the context of this budding science.

  • Edward Witten: Seen as the leading thinker of string theory, Witten introduced the concept of M-theory in 1995 as a way to consolidate the existing string theories. Witten’s work also included the 1984 application of Calabi-Yau manifolds to explain the compactification of the extra dimensions.

    Among string theorists, Edward Witten is seen as a guiding light because of his ability to grasp the implications of the complex mathematics of the theory on a level that few others have been able to match.

  • John Henry Schwarz: At a time when virtually every other physicist abandoned string theory, Schwarz persevered for almost a decade as one of the few who tried to work out the theory’s mathematical details, even though it hurt his career. Eventually, his work led to the first superstring revolution.

    In 1984, Schwarz performed (along with Michael Green) the work showing that string theory was consistent, triggering the first superstring revolution.

  • Yoichiro Nambu: One of the founders of string theory who independently discovered the physical description of the Veneziano model as vibrating strings, Nambu was already a respected particle physicist for his earlier work in describing the mechanism of spontaneous symmetry breaking in particle physics. Dr. Nambu received the 2008 Nobel Prize in Physics for this work.

  • Leonard Susskind: Susskind is another founder of string theory. As he recounts in his book The Cosmic Landscape: String Theory and the Illusion of Intelligent Design, he saw the original dual resonance model equations and thought they looked similar to equations for oscillators, which led him to create the string description — concurrently with Yoichiro Nambu and Holger Nielson.

  • David Gross: He was one of the physicists who developed the heterotic string theory, one of the major findings of the first superstring revolution.

    Since 1997, Dr. Gross has been the director of the Kavli Institute for Theoretical Physics at the University of California, Santa Barbara. In this capacity, Gross is known not only as a strong advocate for string theory but also as a strong opponent of the anthropic principle as applied to the string theory landscape.

  • Joe Polchinski: Polchinski proved that string theory required objects of more than one dimension, called branes. Although the concept of branes had previously been introduced, Polchinski explored the nature of D-branes. This work was crucial to the second superstring revolution of 1995. Polchinski’s work is seen as fundamental to the development of M-theory, brane world scenarios, and the holographic principle.

  • Juan Maldacena: Juan Maldacena is an Argentine physicist who developed the idea that a duality exists between string theory and a quantum field theory — called the Malcadena duality (or the AdS/CFT correspondence).

  • Lisa Randall: Even among the rare women who choose theoretical physics, Lisa Randall doesn’t fit the mold. She spends her free time on intense rock climbing expeditions but spends her professional days exploring the implications of multidimensional brane worlds as a phenomenologist.

    One of the most intriguing models to come out of her analysis of brane world scenarios are the Randall-Sundrum models, which explore the possibility of gravity behaving differently off of our own 3-brane.

  • Michio Kaku: Physicist Michio Kaku has been one of the most vocal supporters of string theory. He worked on the theory early in the 1970s, actually co-founding “string field theory” by writing string theory in a field form.

    By his own account, he then abandoned work on string theory because he didn’t believe in the additional dimensions the theory demanded. He returned to string theory during the first superstring revolution and has proven an entertaining and lucid spokesman ever since.

  • Brian Greene: Last but certainly not least is probably one of the best-known string theorists, especially among nonphysicists. Brian Greene’s popularity as a writer and spokesman for the field dates back to his 1999 book The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory, which was used in 2003 as the basis for a three-part PBS Nova special.

    In 2004, Greene followed up with the book The Fabric of the Cosmos: Space, Time, and the Fabric of Reality. (He has appeared on Comedy Central’s The Colbert Report at least twice, outdoing Dr. Randall’s one appearance.)