Higher-dimensional symmetry of AdS2×S2 correlators

It was recently shown that IIB supergravity on AdS5×S5 enjoys 10d conformal symmetry and that superstring theory on this background can be described using a 10d scalar effective field theory. In this paper we adapt these two complementary approaches to correlators of hypermultiplets in AdS2×S2. In particular, we show that 4-point correlators of 1/2-BPS operators in the 1d boundary can be computed using 4d conformal symmetry and a 4d effective action in the bulk. The 4d conformal symmetry is realised by acting with Casimirs of SU(1, 1|2), and is generically broken by higher derivative corrections. We point out similar structure underlying α′ corrections to IIB supergravity in AdS5×S5. In particular, while the α′3 corrections can be written in terms of a sixth order Casimir acting on a 10d conformal block, similar structure does not appear in higher-order corrections. We note however that a specific combination of higher derivative corrections can give rise to Witten diagrams with higher dimensional symmetry at the integrand level, with breaking then arising from the measure