Modern Physics for Scientists and Engineers, 4th Edition

Book Preface

Our objective in writing this book was to produce a textbook for a modern physics course of either one or two semesters for physics and engineering students. Such a course normally follows a full-year, introductory, calculus-based physics course for freshmen or sophomores. Before each edition we have the publisher send a questionnaire to users of modern physics books to see what needed to be changed or added. Most users like our textbook as is, especially the complete coverage of topics including the early quantum theory, subfi elds of physics, general relativity, and cosmology/astrophysics. Our book continues to be useful for either a one- or two-semester modern physics course. We have made no major changes in the order of subjects in the fourth edition.

Coverage

The first edition of our text established a trend for a contemporary approach to the exciting, thriving, and changing field of modern science. After briefly visiting the status of physics at the turn of the last century, we cover relativity and quantum theory, the basis of any study of modern physics. Almost all areas of science depend on quantum theory and the methods of experimental physics. We have included the name Quantum Mechanics in two of our chapter titles (Chapters 5 and 6) to emphasize the quantum connection. The latter part of the book is devoted to the subfields of physics (atomic, condensed matter, nuclear, and particle) and the exciting fi elds of cosmology and astrophysics. Our experience is that science and engineering majors particularly enjoy the study of modern physics after the sometimes-laborious study of classical mechanics, thermodynamics, electricity, magnetism, and optics. The level of mathematics is not difficult for the most part, and students feel they are finally getting to the frontiers of physics. We have brought the study of modern physics alive by presenting many current applications and challenges in physics, for example, nanoscience, high-temperature superconductors, quantum teleportation, neutrino mass and oscillations, missing dark mass and energy in the universe, gamma-ray bursts, holography, quantum dots, and nuclear fusion. Modern physics texts need to be updated periodically to include recent advances. Although we have emphasized modern applications, we also provide the sound theoretical basis for quantum theory that will be needed by physics majors in their upper division and graduate courses.

Changes for the Fourth Edition

Our book continues to be the most complete and up-to-date textbook in the modern physics market for sophomores/juniors. We have made several changes for the fourth edition to aid the student in learning modern physics. We have added additional end-ofchapter questions and problems and have modifi ed many problems from earlier editions, with an emphasis on including more real-world problems with current research applications whenever possible. We continue to have a larger number of questions and problems than competing textbooks, and for users of the robust Thornton/Rex Modern Physics for Scientists and Engineers, third edition course in WebAssign, we have a correlation guide of the fourth edition problems to that third edition course.

We have added additional examples to the already large number in the text. The pedagogical changes made for the third edition were highly successful. To encourage and support conceptual thinking by students, we continue to use conceptual examples and strategy discussion in the numerical examples. Examples with numerical solutions include a discussion of what needs to be accomplished in the example, the procedure to go through to find the answer, and relevant equations that will be needed. We present the example solutions in some detail, showing enough steps so that students can follow the solution to the end. We continue to provide a signifi cant number of photos and biographies of scientists who have made contributions to modern physics. We have done this to give students a perspective of the background, education, trials, and efforts of these scientists. We have also updated many of the Special Topic boxes, which we believe provide accurate and useful descriptions of the excitement of scientifi c discoveries, both past and current. Chapter-by-Chapter Changes We have rewritten some sections in order to make the explanations clearer to the student. Some material has been deleted, and new material has been added. In particular we added new results that have been reported since the third edition. This is especially true for the chapters on the subfields of physics, Chapters 8–16. We have covered the most important subjects of modern physics, but we realize that in order to cover everything, the book would have to be much longer, which is not what our users want. Our intention is to keep the level of the textbook at the sophomore/ junior undergraduate level. We think it is important for instructors to be able to supplement the book whenever they choose—especially to cover those topics in which they themselves are expert. Particular changes by chapter include the following:
• Chapter 2: we have updated the search for violations of Lorentz symmetry and added some discussion about four vectors.
• Chapter 3: we have rewritten the discussion of the Rayleigh-Jeans formula and Planck’s discovery.
• Chapter 9: we improved the discussion about the symmetry of boson wave functions and its application to the Fermi exclusion principle and Bose-Einstein condensates.
• Chapter 10: we added a discussion of classes of superconductors and have updatedour discussion concerning applications of superconductivity. The latter includes how superconductors are now being used to determine several fundamental constants.
• Chapter 11: we added more discussion about solar energy, Blu-ray DVD devices, increasing the number of transistors on a microchip using new semiconductor materials, graphene, and quantum dots. Our section on nanotechnology is especially complete.
• Chapter 12: we updated our discussion on neutrino detection and neutrino mass, added a description of nuclear magnetic resonance, and upgraded our discussion on using radioactive decay to study the oldest terrestrial materials.
• Chapter 13: we updated our discussion about nuclear power plants operating in the United States and the world and presented a discussion of possible new, improved reactors. We discussed the tsunami-induced tragedy at the Fukushima Daiichi nuclear power plant in Japan and added to our discussion of searches for new elements and their discoveries.
• Chapter 14: we upgraded our description of particle physics, improved and expanded the discussion on Feynman diagrams, updated the search for the Higgs boson, discussed new experiments on neutrino oscillations, and added discussion on matter-antimatter, supersymmetry, string theory, and M-theory. We mention that the LHC has begun operation as the Fermilab Tevatron accelerator is shutting down.
• Chapter 15: we improved our discussion on gravitational wave detection, added to our discussion on black holes, and included the fi nal results of the Gravity Probe B satellite.