These are stylistically informal notes, typically based on lectures. Generally my strategy is to write the notes that I wished were available for me to read before I learned the subject. When transitioning to research, students are often advised not to spend too much time digesting background material, and instead to just get to work on a problem. I’ve been very good at following this advice, so in many cases these notes document my process of actually learning the background associated with a subject not so long after I began to write papers about it.
Contemporary Machine Learning for Physicists was written in 2018 and will likely be updated in early 2021, as there’s quite a bit of room for improvement, especially on statistics and information theory. It focuses on neural network based ML, but has quite a bit of more general background. I hope it’s a great reference for anyone with an advanced physics background who wants to quickly learn about AI.
AdS/CFT Notes were written in 2013 and haven’t changed much since then. At the time of writing my perspective was highly unusual and somewhat novel — I strongly emphasize the generality of the AdS-CFT connection, and the fact that most of its basic features follow inevitably from studying (effective) field theory in AdS or the axiomatic (ie bootstrap) approach to CFT. I mostly ignore specific stringy realizations of AdS/CFT, as I view them as a special case on a more general story. The philosophy was very heavily influenced by Weinberg’s view of QFT as an inevitable consequence of Lorentz invariant quantum mechanical scattering in flat space; in essence I view AdS/CFT as identical to this, replacing QFT -> AdS QFT and the S-Matrix with CFT correlation functions.
Some Quantum Gravity Notes were written in 2019 and combine some standard discussion of horizon thermodynamics (heavily borrowing from Ted Jacobson’s notes) with some much less standard discussions about the inevitability of holography and the still-confusing nature of locality in quantum gravity (specifically, diffeomorphism gauge redundancies).
My Quantum Field Theory Notes combine material from standard textbooks, particularly Weinberg and Schwartz, but also include some less conventional material, including a very early first lecture on effective field theory from balls and springs and some little-known results deriving the practical RG procedure from the Wilsonian RG via “the sawtooth”.