Physics 646, String Theory

Fall 2021

Instructor:

Dr. James Liu
Office: 3409 Randall Laboratory
Email: jimliu@umich.edu
Tel: (734) 763-4314

Class meets:

Mondays and Wednesdays, 10:00-11:30 in 3481 Randall

Office hours:

Mondays and Wednesdays, 3:00-4:00, or by appointment

Introduction:

String theory is a framework originating from quantizing relativistic strings.  While it has led to many new developments, such as AdS/CFT and applications to strongly coupled field theories, this course will focus on the fundamentals of quantized strings and two-dimensional CFT as applied to string theory.  Since there is way more material than can be comprehensively covered in a one-semester course, this course will be selective in the choice of topics.  The aim is to develop a solid understanding of the string worldsheet, with emphasis on the bosonic string, while setting the stage for the superstring and beyond.

Textbook:

Joseph Polchinski, String Theory, Volumes I (required) and II (optional), Cambridge University Press, 2005.  We will cover Chapters 1-8 on the bosonic string and parts of Chapters 10-12 on the superstring.  This set is still the standard reference on the subject, and provides a systematic coverage of the fundamentals.   We will not be able to cover all the material, and will unfortunately omit much of Volume II.  The serious student is encouraged to self-study what we are not able to cover.

Other textbooks you may wish to consult include:

• Green, Schwarz and Witten, Superstring Theory, Volumes 1 and 2
  These was the standard books on string theory before Polchinski came out, and were the ones I learned from.  In contrast with Polchinski, which emphasizes the CFT aspects of the string worldsheet throughout, Green, Schwarz and Witten for the most part works in a more ad hoc manner.  The material on string model building and Calabi-Yau compactification in Volume 2 remains a solid introduction and can be worth going through.
• Zwiebach, A First Course in String Theory
  While this may be considered an advanced undergraduate textbook, it provides a serious introduction to the important concepts in an approachable manner.  This book is highly recommended as a supplement to Polchinski, Volume I, for  anyone looking for additional discussion without getting caught up in the mathematical details.
• Becker, Becker and Schwarz, String Theory and M-Theory
  This book starts with the string action and ends up at modern topics not covered in Polchinski and does it all in one volume.  This is an excellent book to look at for an introduction to some current research topics, but can lack detail on the fundamentals.
• Johnson, D-branes
  As the title suggests, this book emphasizes D-branes and strings at strong coupling.  It is less comprehensive that Polchinski in the foundational issues, but is able to cover more advanced and modern topics.
• Blumenhagen, Lust and Theisen, Basic Concepts of String Theory
  This is a revision of the out of print Lust and Theisen, Lectures on String Theory.  I am not familiar with this book, but have heard good things about it as an approachable and pedagogical textbook that gets the student up to speed on CFT techniques for string theory.
• Kiritsis, String Theory in a Nutshell
• An earlier book, Introduction to Superstring Theory, is available on the arXiv as hep-th/9709062.  Again, I am not familiar with this book, but it takes the student from the basics to advanced research topics.  As such, it is rather condensed (hence the `Nutshell' description).

Web site:

The home page for this class is hosted by Canvas, and may be accessed from http://canvas.umich.edu/
(Title: PHYSICS 646 001 FA 2021).  Course information, including the syllabus, homeworks and announcements, are available from the course page.

Class format:

This is an in-person course that meets in 3481 Randall (the Oskar Klein room).  However, we may need to switch to an online format if the situation warrants it.  If this happens, the plan is to have synchronous online lectures conducted via Zoom during the normal class meeting times.

Recordings:

In-person lectures will not be recorded.  However, in the event we switch to online lectures, the online lectures will be audio/video recorded and made available to students in this course.  If you do not wish to be recorded during online lectures (if any take place), please contact me by email prior to any such lectures to discuss alternative arrangements.

Homework:

There will be 11 homework assignments, due once a week on most Mondays at the beginning of lecture.  Homeworks will be posted on Canvas at least one week before their due date, and solutions will be available afterwards.  I will look through everyone's homework assignments, and will make comments as appropriate, but will not grade them in the usual sense.  Instead, each problem will be worth one point, and any serious attempt will be sufficient for earning credit for that problem.  I expect all students who have signed up for this course to be serious about learning the material.  The homework assignments are intended to help you learn, and I expect you to complete all problems and to review the posted solutions as part of the learning process.

String theory and CFT can be a difficult subject, and I encourage you to study and work on homework together.  However, I expect each student to turn in original work.  Late homework is not accepted, except by prior arrangement.

Project:

There will be no exams in this course.  However, you will be expected to complete a term project.  Due to the limitations of a one-semester course, we will necessarily leave many topics uncovered, but this does not prevent you from studying more advanced topics.  Hence the idea of the project is for you to choose a topic of your interest and to explore it in more detail.  Good projects can be based on material in Polchinski Volume II or some of the textbooks mentioned above.  In any case, I expect to discuss project ideas with each of you individually.  The plan of the project is to pick a topic, study it on your own, and write a report of what you learned.  Your project topic should be in place by the end of October, and reports are due on the day of our last lecture, namely Wednesday, December 8.

Grading:

This course is graded S/U.  To obtain a satisfactory grade, you are expected to attend most class lectures, complete all homework assignments and complete the project.

Honesty:

All students are expected to take personal responsibility for upholding the standards of academic integrity of the University community. Any student determined to have engaged in any form of academic dishonesty, including but not limited to plagiarism, cheating, and copying homework, will receive a zero on the assignment.

In accordance with University policy, all cases of misconduct will be reported to the Rackham Resolution Officer. If you have any questions, please contact me by email.

Culture of care:

The University is committed to delivering our mission while aiming to protect the health and safety of the community, which includes minimizing the spread of COVID-19. Our entire community is responsible for protecting the collective health of all members by being mindful and respectful in carrying out the guidelines laid out in our Wolverine Culture of Care and the University's Face Covering Policy for COVID-19. Individuals seeking to request an accommodation related to the face covering requirement under the Americans with Disabilities Act should contact the Office for Institutional Equity.

In our classrooms all students are expected to adhere to the required safety measures and guidelines of the State of Michigan and the University of Michigan, wearing a face covering that covers the mouth and nose in all classrooms, and not coming to class when ill or in quarantine. It is important to also be thoughtful about group gatherings as well as about classroom activities and exercises that require collaboration. 

Any student who is not able and willing to comply with campus safety measures while attending the in-person lectures should contact me or their academic advisor to discuss alternate participation or course options.  Students who do not adhere to these safety measures while in a face-to-face class setting, and do not have an approved exception or accommodation, will be asked to disenroll from the class.

[PDF syllabus]

[PDF schedule]