Abstract
We observe a direct relation between the existence of fundamental axionic strings, dubbed EFT strings, and infinite distance limits in 4d mathcal{N} = 1 EFTs coupled to gravity. The backreaction of EFT strings can be interpreted as RG flow of their couplings, and allows one to probe different regimes within the field space of the theory. We propose that any 4d EFT infinite distance limit can be realised as an EFT string flow. We show that along such limits the EFT string becomes asymptotically tensionless, and so the EFT eventually breaks down. This provides an upper bound for the maximal field range of an EFT with a finite cut-off, and reproduces the Swampland Distance Conjecture from a bottom-up perspective. Even if there are typically other towers of particles becoming light, we propose that the mass of the leading tower scales as m2 ∼ mathcal{T} w in Planck units, with mathcal{T} the EFT string tension and w a positive integer. Our results hold even in the presence of a non-trivial potential, as long as its energy scale remains well below the cut-off. We check both proposals for large classes of 4d mathcal{N} = 1 string compactifications, finding that only the values w = 1, 2, 3 are realised.
Highlights
One pressing problem for Effective Field Theories (EFTs) of quantum gravity is to determine which kind of physics one can obtain at regions of weak coupling
Every infinite field distance limit of a 4d EFT consistent with quantum gravity can be realised as an renormalisation group (RG) flow UV endpoint of an EFT string
In this work we have studied the physics emerging at large field distances of 4d N = 1 EFTs by characterising the asymptotic limits in terms of fundamental axionic BPS strings, dubbed EFT strings
Summary
One pressing problem for Effective Field Theories (EFTs) of quantum gravity is to determine which kind of physics one can obtain at regions of weak coupling. By the no global symmetry conjecture [35, 36], one expects that for EFTs coupled to quantum gravity such exact shift symmetries are located at infinite distance points in field space, with some mechanism preventing the EFT to ever reach them, to the setup in [37] These solutions are suitable to study the physics of the SDC from an EFT perspective. They characterise the asymptotic limits of infinite distance of a 4d EFT in terms of EFT string flows, and have interesting implications for several swampland criteria. Appendix E discusses the backreaction and flows associated to 4d instantons
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have