What defines gravity? In this talk, I will study effective field theories with anomalous higher-form symmetries. I will explain how we can use the anomalous conservation equations that are present in these theories to fix unambiguously the two-point function between conserved currents. Performing a Kallen-Lehmann decomposition of this correlator, I will go on to show a version of Goldstone’s theorem, thus proving that these EFTs have a gapless mode in their spectrum., and that it is protected by the anomaly. Furthermore, the anomaly gives rise to a universal form of the EFT whose most relevant term—which resembles the linear Einstein action—dominates the infrared physics. I will then present a slightly different type of higher-form symmetries that linearized general relativity possess. This global symmetry structure is sufficient to show that this theory must have a massless spin 2 in its spectrum, which is the graviton.
Host - Petar Tadic (petar.tadic@yale.edu)