TY - GEN
T1 - Quantum geometry in superfluidity and superconductivity
AU - Peotta, Sebastiano
AU - Huhtinen, Kukka Emilia
AU - Törmä, Päivi
N1 - Publisher Copyright: © Società Italiana di Fisica
PY - 2025/1/22
Y1 - 2025/1/22
N2 - We review the theoretical description of the role of quantum geometry in superfluidity and superconductivity of multiband systems, with focus on flat bands where quantum geometry is wholly responsible for supercurrents. This review differs from previous ones in that it is based on the most recent understanding of the theory: the dependence of the self-consistent order parameter on the supercurrent is properly taken into account, and the superfluid weight in a flat band becomes proportional to the minimal quantum metric. We provide a recap of basic quantum geometric quantities and the concept of superfluid density. The geometric contribution of superconductivity is introduced via considering the two-body problem. The superfluid weight of a multiband system is derived within mean-field theory, leading to a topological bound of flat band superconductivity. The physical interpretation of the flat band supercurrent in terms of Wannier function overlaps is discussed.
AB - We review the theoretical description of the role of quantum geometry in superfluidity and superconductivity of multiband systems, with focus on flat bands where quantum geometry is wholly responsible for supercurrents. This review differs from previous ones in that it is based on the most recent understanding of the theory: the dependence of the self-consistent order parameter on the supercurrent is properly taken into account, and the superfluid weight in a flat band becomes proportional to the minimal quantum metric. We provide a recap of basic quantum geometric quantities and the concept of superfluid density. The geometric contribution of superconductivity is introduced via considering the two-body problem. The superfluid weight of a multiband system is derived within mean-field theory, leading to a topological bound of flat band superconductivity. The physical interpretation of the flat band supercurrent in terms of Wannier function overlaps is discussed.
UR - http://www.scopus.com/inward/record.url?scp=105000406799&partnerID=8YFLogxK
UR - https://www.iospress.com/catalog/books/quantum-mixtures-with-ultra-cold-atoms
U2 - 10.3254/ENFI250023
DO - 10.3254/ENFI250023
M3 - Conference article in proceedings
AN - SCOPUS:105000406799
T3 - Proceedings of the International School of Physics "Enrico Fermi"
SP - 373
EP - 404
BT - Proceedings of the International School of Physics "Enrico Fermi", Course 211 "Quantum Mixtures with Ultra-Cold Atoms
A2 - Grimm, Rudolf
A2 - Inguscio, Massimo
A2 - Stringari, Sandro
A2 - Lamporesi, Giacomo
PB - IOS Press
T2 - International School of Physics "Enrico Fermi"
Y2 - 18 July 2022 through 23 July 2022
ER -