Live Blogging: Vistarini

Tiziana’s going to talk about emergenet spacetime in string theory…

When we have a theory that’s so far ahead of our ability to test it, emergence of spacetime is going to be an important test.

But of course we need to define a notion of emergence! She’s going to focus on emergence of ordinary 4D GR spacetime – not discussing emergence of, say, one exotic spacetime from another in the case of dualities.

2 ingredients: First, string theory predicts the existence of spin-2 particles (gravitons). What does this mean? The particle appears in the spectrum of states of the quantum state – has the right mathematical properties to describe the postulated physical particle. Let’s keep that first ingredient in the back of our mind, but focus on the second…

Second ingredient: Derivation of GR from string theory (as discussed by Huggett yesterday).

So on the one hand we have gravitons, and on the other the idea that we get a background metric that obeys the Einstein Field Equations. Together these give us emergence of spacetime.

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