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mitchell porter
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The annual big string theory conference took place last week. I thought I would make a thread about it, partly because the most prominent post about it anywhere, is probably Peter Woit dismissing it as worthless.
I skimmed the live video (links here to slides, videos, and posters). What did I personally find to be of interest?
Lara Anderson gave a talk about topology change in heterotic vacua, i.e. transitions between different Calabi-Yau manifolds in the extra dimensions, which turn out to be mediated by the appearance of five-branes. For me there was something classical about this topic, reminiscent of the glory days of the early 1990s when all the different string theories were being unified via duality under the aegis of M-theory. In this case one is trying to go further, and understand how all the different vacua of the string landscape are connected. Brian Greene had some interest in this topic in the late 1990s, and then thanks to Susskind, the landscape was important in the 2000s, but more because that was how the anthropic principle entered the mainstream of string theory.
Apparently there is a revival of the "IKKT model", a matrix model from Japan. The best known matrix model is BFSS, which is a model of M-theory. IKKT, on the other hand, is supposed to be a model for the emergence of the time dimension. I haven't studied it at all.
There was a session on the topic of von Neumann algebras in quantum gravity; Witten spoke in this session. Hong Liu addressed a topic of AdS/CFT - why is physics local in the emergent dimensions - by introducing a "subalgebra-subregion duality", between subalgebras of the CFT on the boundary, and subregions of the emergent bulk spacetime.
During the panel discussions on the final day, Renata Kallosh said that there would soon be more data on the tensor-to-scalar ratio in the CMB, and seemed to think that a particular string model would favor Higgs inflation or Starobinsky inflation (which was the original form of inflation suggested in Russian physics literature).
I skimmed the live video (links here to slides, videos, and posters). What did I personally find to be of interest?
Lara Anderson gave a talk about topology change in heterotic vacua, i.e. transitions between different Calabi-Yau manifolds in the extra dimensions, which turn out to be mediated by the appearance of five-branes. For me there was something classical about this topic, reminiscent of the glory days of the early 1990s when all the different string theories were being unified via duality under the aegis of M-theory. In this case one is trying to go further, and understand how all the different vacua of the string landscape are connected. Brian Greene had some interest in this topic in the late 1990s, and then thanks to Susskind, the landscape was important in the 2000s, but more because that was how the anthropic principle entered the mainstream of string theory.
Apparently there is a revival of the "IKKT model", a matrix model from Japan. The best known matrix model is BFSS, which is a model of M-theory. IKKT, on the other hand, is supposed to be a model for the emergence of the time dimension. I haven't studied it at all.
There was a session on the topic of von Neumann algebras in quantum gravity; Witten spoke in this session. Hong Liu addressed a topic of AdS/CFT - why is physics local in the emergent dimensions - by introducing a "subalgebra-subregion duality", between subalgebras of the CFT on the boundary, and subregions of the emergent bulk spacetime.
During the panel discussions on the final day, Renata Kallosh said that there would soon be more data on the tensor-to-scalar ratio in the CMB, and seemed to think that a particular string model would favor Higgs inflation or Starobinsky inflation (which was the original form of inflation suggested in Russian physics literature).
