I’m at Amplitudes this week, in Stockholm.
Last year, I wrote a post giving a tour of the field. If I had to write it again this year most of the categories would be the same, but the achievements listed would advance in loops and legs, more complicated theories and more insight.
The ambitwistor string now goes to two loops, while my collaborators and I have pushed the polylogarithm program to five loops (dedicated post on that soon!) A decent number of techniques can now be applied to QCD, including a differential equation-based method that was used to find a four loop, three particle amplitude. Others tied together different approaches, found novel structures in string theory, or linked amplitudes techniques to physics from other disciplines. The talks have been going up on YouTube pretty quickly, due to diligent work by Nordita’s tech guy, so if you’re at all interested check it out!