{"id":12381,"date":"2021-06-21T16:27:25","date_gmt":"2021-06-21T20:27:25","guid":{"rendered":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=12381"},"modified":"2021-07-02T16:21:57","modified_gmt":"2021-07-02T20:21:57","slug":"strings-2021","status":"publish","type":"post","link":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=12381","title":{"rendered":"Strings 2021"},"content":{"rendered":"

Strings 2021 started today, program is available here<\/a>. Since it’s online only, talks are much more accessible than usual (and since it’s free, over 2000 people have registered to in principle participate via Zoom). Talks are available for watching every day via Youtube, links are on the main page<\/a>.<\/p>\n

As has been the case for many years, it doesn’t look like there will be anything significantly new on the age-old problems of getting fundamental physics out of a string theory. But, as has also been the case for many years, the conference features many talks that have nothing to do with string theory and may be quite interesting. I notice that Roger Penrose, a well-know string theory skeptic, will be giving a talk on the last day of the conference next week.<\/p>\n

Another series of talks that I took a look at and that I can recommend is Nima Arkani-Hamed’s lectures on Physics at Future Colliders at the ICTP summer school on particle physics<\/a>. He never actually gets anywhere near discussing the topic of the title for the talks, but does give a very nice leisurely introduction to computing amplitudes for zero-mass particles. What he’s doing is emphasizing ideas that are often not taught in conventional QFT courses (although they should be). His second talk explains how to think of things in terms of classifying representations of the Poincare group, an old topic that unfortunately is often no longer taught (see chapter 42 of my QM textbook). His third talk emphasizes thinking of space-time vectors as two by two matrices (see section 40.4 of my QM book). This is a truly fundamental idea about space time geometry that gets too little attention in most physics courses.<\/p>\n

Update<\/strong>: At String 2021, yesterday Nima Arkani-Hamed gave a talk on “Connecting String Theory to the Real World We See Outside Our Windows”<\/a>, where he sometimes sounds like me, contrasting the pre-LHC claims of string theorists:<\/p>\n

1. LHC will discover SUSY
\n2. String Theory Loves SUSY + Unification<\/p><\/blockquote>\n

to what they are saying now that the LHC has found no SUSY<\/p>\n

CICADAS [i.e. crickets]. (Anyway, String Theory is mainly about Quantum Gravity).<\/p><\/blockquote>\n

He goes on to explain the “landscape philosophy”, which he sees string theorists (and himself) as now adopting. According to this philosophy, “connection to particle physics appear[s] hopeless\/”parochial”\/unimportant”. As a result, he sees the current situation as<\/p>\n