Fermi surface reconstruction using ancilla spins - NRG + DMFT study
The transition from a conventional metal with a large Fermi surface to a metal with a small Fermi surface, violating Luttingers theorem, is currently of major interest. Such Fermi surface reconstructions can be found in various materials, for example heavy-fermion compounds [1] and cuprate high-T_c superconductors [2]. In a recent paper [3], Zhang and Sachdev propose a Hubbard model with ancilla spins for such a transition, which they solve with a static mean-field Ansatz. However, the proposed model may also be treated using the Dynamical Mean-Field Theory (DMFT) together with the Numerical Renormalization Group (NRG) to obtain a picture going beyond the static mean-field description.
The project aims at comparing the findings of [3] with the DMFT solution to the model, using code provided by our group.
Mentor: andreas.gleis@physik.uni-muenchen.de
[1] S. Paschen et al., https://www.nature.com/articles/nature03129
[2] S. Badoux et al., https://www.nature.com/articles/nature16983
[3] Y. Zhang and S. Sachdev, https://arxiv.org/abs/2001.09159