String Theory and Our Universe by Cumrun Vafa

This is an online seminar series on string field theory (SFT) and related topics (worldsheet theory, string amplitudes, compactifications, homotopy algebras…) on Thursday every 2 weeks. Talks are 1.5 hours long: the recommended format is a general introduction of 30 min for students and non-specialists (especially before technical talks), followed by 1 hour of talk + discussions intertwined.

Abstract: String theory landscape of vacua point to new consistency conditions that a quantum gravitational system must satisfy. There are only a small number of quantum field theories that satisfy these conditions, and all the rest belong to the `Swampland', which cannot be consistently coupled to gravity. In this talk, I review some of these conditions and their implications for cosmology and particle physics.

[gilleslalancette]

excellent presentation from mister Vafa. I love it, it is clear, concise and full of great links into various physics. Thanks for presenting this.

[annaclarafenyo]

The black hole argument for the charge completeness condition can be violated by conspiracy, for example, particles of charges 2, 4, 8, 16, 32, 64, 128, 256 and 77. A charge-1 state required "exists" but only as a parallel comoving combination of particles and anti-particles, and you can combine the charges to make any integer. The argument requires a more careful formulation to avoid these ridiculous conspiracies (I agree they do not occur).

[msgfreenetde]

if i put two identical strings on top of each other - so each point of string A meets each point of string B - what is the distance between these 2 strings? zero?! so r^-2 is infinity again? seems there is no gain at all...

[msgfreenetde]

Why string-theory decided to declare particles as vibrating stuff? why not declare the space and time as vibrating?

[DavidBrown-omcv]

" As long as there is no gravity in the game, we know how everything works." Without gravity, there would no planet Earth & no human life.
Consider 2 hypotheses: (1) String theory (in some form) is the only mathematically plausible way to unify quantum field theory & general relativity theory. (2) The main problem with string theory is that the string theorists refuse to carefully study the many empirical successes of Milgrom's MOND. Is hypothesis (2) wrong? Please google "pavel kroupa green schwarz".