Flower Hill
 

Strings

An introduction for high school students 

(and beyond)


Bob Dorsett

Wyethia and Lupine near Kebler Pass, Colorado.   Bob Dorsett.

Page last updated:  02/17/2025




Here you will find links to my text on string theory, one of the most exciting developments in theoretical physics.  String theory has become an essential tool in physics.  It provides new insight into a broad range of outstanding questions in nuclear physics, condensed matter physics, black holes, and cosmology.  I think high school students with an introductory background in physics and calculus can understand its basic concepts.  This text is for them and for anyone with a similar background.  

I based the chapters largely on Leonard Susskind's marvelous lectures on string theory, part of his course series in The Theoretical Minimum offered by the Stanford Office of Continuing Education.  Professor Susskind kindly offered encouragement in this endeavor and permission to post online.  Any errors -- and I am sure there are some -- are mine and not his.  
If you see any, please let me know.  

Contents with chapter links follow, and further down the page you will find links to other resources as well.  Note that the Return to Table of Contents links, found at the end of each chapter, don't work after this latest update.  Just click on the Contents tab on your browser. 

I hope you enjoy exploring these ideas as much as I have.  

Contents

ChapterTitle

Introduction

Math conventions 
1What are strings?
2Light cone analysis
3Strings as springs
4Dirichlet and Neumann boundaries
5Open string modes
6Quantizing the string
7The tachyon problem
8Closed strings and level matching
9The closed string spectrum
10Circular polarization
11Extra dimensions
12Compactification
13Feynman diagrams
14String scattering
15Veneziano amplitude
16Conformal invariance
17Conformal invariance reprise
18String interaction amplitude
19Ricci flat space
20T-duality
21D-branes
22Branes and quantum field theory
23Fields in extra dimensions
24S-duality
25Black hole basics
26Black hole temperature
27Black hole entropy
28String entropy of a black hole
29Entropy and holography
30Black hole horizon
31Cosmic horizon
32History of the universe
33de Sitter space
34Beyond the horizon
35Where next?
36Questions and conjectures
37Epilogue:  lessons from strings


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Links to other String Resources: Return to Table of Contents



The Picture:

The photograph shows a typical subalpine community in the central Colorado Rockies, including a population of Wyethia (Mule's ears, the large yellow composites), lupine (purple flower in the left foreground) and, on the skyline, alpine fir.  Living organisms in this environment must adapt to harsh extremes -- cold winters with heavy snowfall, hot and dry summers.  If all the multiverse is string, here are strings at work.  (And I like the picture.)

 



BrainTeasers:

Make the following equation in Roman numerals using matchsticks:

    | + || + ||| + |||| =

Move one matchstick to a new location in the equation so that the sum equals 4.

Car Talk Puzzlers

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Contact:

dorsett.bob@gmail.com



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