4D dS vacua from AdS vacua of type IIB string theory and the AdS distance conjecture

In order for string theory to be made compatible with the low-energy observations of a positive cosmological constant, there have been attempts to construct de Sitter (dS) vacua in string theory which are particularly difficult to realize. Instead of attempting to find dS vacuum solutions, we point to a new way to make string theory consistent with low-energy dS cosmology. In this way, string theory lives in an anti-de Sitter (AdS) vacuum (which is simple to construct) that exists only in the high-energy regime; however, as going to the low-energy scales where the heavy string excitations and Kaluza-Klein modes are integrated out, we show that the effective picture of string theory in lower dimensions would exhibit a 4D dS vacuum without needing to add additional structures such as anti-D3 branes. Additionally, we point to evidence from bottom-up physics for the strong version of the AdS distance conjecture realized from AdS vacua in string theory. This evidence, hence, supports the sharpening of the AdS distance conjecture as one of the universal features of quantum gravity.