New preprint announcement

We are excited to announce the submission of our latest preprint to arXiv, titled Nevanlinna Analytic Continuation for Migdal-Eliashberg Theory. In this work, we introduce a novel method that overcomes the current challenges in obtaining real-frequency properties from Migdal-Eliashberg (ME) theory for superconductivity.

ME theory is central to understanding superconductors, but translating the results from the theory’s native imaginary frequency space to experimentally relevant real frequency space has always been a complex process. Traditional approaches involve decomposing the ME Green’s function into components that lose the causal structure of Green’s functions, making analytic continuation — an essential step — difficult or unreliable.

Our new approach retains the causal properties of Green’s functions, allowing the application of analytic continuation techniques, such as Nevanlinna, that were previously impractical for this problem. We demonstrate the accuracy and effectiveness of our method through applications to superconductors like MgB2 and LaBeH8, achieving real-frequency results that can be directly compared with experimental data.

This advancement opens new avenues for studying superconductivity and could significantly impact the interpretation of experimental measurements in this field. We look forward to sharing more details and receiving feedback from the scientific community!

Check out the preprint arXiv:2409.02737.