article published yes Sven Joscha Henheik author 31d731d7-d235-11ea-ad11-b50331c8d7fb0000-0003-1106-327X Asbjørn Bækgaard Lauritsen author e1a2682f-dc8d-11ea-abe3-81da9ac728f10000-0003-4476-2288 LaEr department RoSe department Random matrices beyond Wigner-Dyson-Mehta project Mathematical Challenges in BCS Theory of Superconductivity project We consider the BCS energy gap „.T / (essentially given by „.T / .T; p/, the BCS order parameter) at all temperatures 0 T Tc up to the critical one, Tc, and show that, in the limit of weak coupling, the ratio „.T /=Tc is given by a universal function of the relative temperature T =Tc. On the one hand, this recovers a recent result by Langmann and Triola [Phys. Rev. B 108 (2023), no. 10, article no. 104503] on three-dimensional s-wave superconductors for temperatures bounded uniformly away from Tc. On the other hand, our result lifts these restrictions, as we consider arbitrary spatial dimensions d 2 ¹1; 2; 3º, discuss superconductors with non-zero angular momentum (primarily in two dimensions), and treat the perhaps physically most interesting (due to the occurrence of the superconducting phase transition) regime of temperatures close to Tc. ​ . https://research-explorer.ista.ac.at/download/19548/19549/Henheik_JSpectralTheory_2025.pdf application/pdfno EMS Press2025 eng 1664-0403 2312.11310 00143893160000910.4171/JST/540 151305–352 https://research-explorer.ista.ac.at/record/19540 Henheik SJ, Lauritsen AB. Universal behavior of the BCS energy gap. <i>Journal of Spectral Theory</i>. 2025;15(1):305–352. doi:<a href="https://doi.org/10.4171/JST/540">10.4171/JST/540</a> S.J. Henheik, A.B. Lauritsen, Journal of Spectral Theory 15 (2025) 305–352. Henheik, Sven Joscha, and Asbjørn Bækgaard Lauritsen. “Universal Behavior of the BCS Energy Gap.” <i>Journal of Spectral Theory</i>, vol. 15, no. 1, EMS Press, 2025, pp. 305–352, doi:<a href="https://doi.org/10.4171/JST/540">10.4171/JST/540</a>. Henheik SJ, Lauritsen AB. 2025. Universal behavior of the BCS energy gap. Journal of Spectral Theory. 15(1), 305–352. S. J. Henheik and A. B. Lauritsen, “Universal behavior of the BCS energy gap,” <i>Journal of Spectral Theory</i>, vol. 15, no. 1. EMS Press, pp. 305–352, 2025. Henheik, S. J., &#38; Lauritsen, A. B. (2025). Universal behavior of the BCS energy gap. <i>Journal of Spectral Theory</i>. EMS Press. <a href="https://doi.org/10.4171/JST/540">https://doi.org/10.4171/JST/540</a> Henheik, Sven Joscha, and Asbjørn Bækgaard Lauritsen. “Universal Behavior of the BCS Energy Gap.” <i>Journal of Spectral Theory</i>. EMS Press, 2025. <a href="https://doi.org/10.4171/JST/540">https://doi.org/10.4171/JST/540</a>. 195482025-04-11T09:19:28Z2026-04-07T12:37:11Z