Physics 234B: String Theory II

Quantum Gravity and Unifications

Spring 2015

Basic Info

Time: lectures: Tue and Thu, 12:40-2pm.
discussions: TBD.

Place: 402 Le Conte Hall

Instructor: Petr Hořava (email:
Office: 401 Le Conte Hall.

This year, our focus in the 234B course will be on gravity -- both classical and quantum, how it emerges from string and superstring theory, whether it can have an independent life outside of strings, how it enters into various dualities and unifications across different areas of physics (from supersymmetric unifications with the Standard Model of particle physics, to unifications with non-gravitational physics via the AdS/CFT correspondence and other dualities, to nonrelativistic Lifshitz gravity and its relation to the Causal Dynamical Triangulations approach to quantum gravity, to applications in condensed matter physics). We will also discuss some of the many fundamental open puzzles of gravity.

More details about the course will be posted here in due time.


On the gravity side, basics of General Relativity at the level of 231 are required. On the quantum side, basics of QFT at the level of 232A would be a good start, and will effectively be required.

On the other hand, basics of Yang-Mills gauge theories (either 233A or 232B) would also be useful, but will not be strictly required for students who wish to sign up for this course. Same with the basics of String Theory -- it would be useful and nice to have seen strings (at the level of 234A), but it will not be formally required in order to take this course. If you are interested in this course and have questions about having all the prerequisites, feel free to talk to me (in person or via email); I will try to be flexible, so that we can accommodate as many students in this course as possible, even those who come from various diverse backgrounds such as particle phenomenology, cosmology, condensed matter, or pure math.

Homeworks and Reading Assignments

There will be no homework sets for this course. Instead, there will be a list of reading assignments, where each student gets to choose one from the list of many important gravity-related research papers. Then, in the second half of the semester, the students will present their summary of the ideas and results of their chosen paper during our Discussion Sessions. The final grade will be based on this presentation. There will be no final exam.