@article{19548,
  abstract     = {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.

​
 .},
  author       = {Henheik, Sven Joscha and Lauritsen, Asbjørn Bækgaard},
  issn         = {1664-0403},
  journal      = {Journal of Spectral Theory},
  number       = {1},
  pages        = {305–352},
  publisher    = {EMS Press},
  title        = {{Universal behavior of the BCS energy gap}},
  doi          = {10.4171/JST/540},
  volume       = {15},
  year         = {2025},
}

@article{14662,
  abstract     = {We consider a class of polaron models, including the Fröhlich model, at zero total momentum, and show that at sufficiently weak coupling there are no excited eigenvalues below the essential spectrum.},
  author       = {Seiringer, Robert},
  issn         = {1664-0403},
  journal      = {Journal of Spectral Theory},
  number       = {3},
  pages        = {1045--1055},
  publisher    = {EMS Press},
  title        = {{Absence of excited eigenvalues for Fröhlich type polaron models at weak coupling}},
  doi          = {10.4171/JST/469},
  volume       = {13},
  year         = {2023},
}

@article{13207,
  abstract     = {We consider the linear BCS equation, determining the BCS critical temperature, in the presence of a boundary, where Dirichlet boundary conditions are imposed. In the one-dimensional case with point interactions, we prove that the critical temperature is strictly larger than the bulk value, at least at weak coupling. In particular, the Cooper-pair wave function localizes near the boundary, an effect that cannot be modeled by effective Neumann boundary conditions on the order parameter as often imposed in Ginzburg–Landau theory. We also show that the relative shift in critical temperature vanishes if the coupling constant either goes to zero or to infinity.},
  author       = {Hainzl, Christian and Roos, Barbara and Seiringer, Robert},
  issn         = {1664-0403},
  journal      = {Journal of Spectral Theory},
  number       = {4},
  pages        = {1507–1540},
  publisher    = {EMS Press},
  title        = {{Boundary superconductivity in the BCS model}},
  doi          = {10.4171/JST/439},
  volume       = {12},
  year         = {2023},
}