Dynamical structure factor and a new method to measure the pairing gap in two-dimensional attractive Fermi–Hubbard model
Year: 2025
Type: article
Abstract: The measurement of the pairing gap is crucial for investigating the physical properties of superconductors or superfluids. We propose a strategy to measure the pairing gap through the dynamical excitations. With the random phase approximation (RPA), we study the dynamical excitations of a two-dimensional attractive Fermi–Hubbard model by calculating its dynamical structure factor. Two distinct collective modes emerge: a Goldstone phonon mode at transferred momentum q = [0,0] and a roton mode at q = [ π , π ]. The roton mode exhibits a sharp molecular peak in the low-energy regime. Notably, the area under the roton molecular peak scales with the square of the pairing gap, which holds even in three-dimensional and spin–orbit coupled (SOC) optical lattices. This finding suggests an experimental approach to measure the pairing gap in lattice systems by analyzing the dynamical structure factor at q = [ π , π ].
Source: Chinese Physics B
Authors: Huaisong 怀松 Zhao 赵, Feng 峰 Yuan 袁, Tianxing 天星 Ma 马, Peng 鹏 Zou 邹
Institutions: Qingdao University, Beijing Normal University
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,500
OpenAlex ID: W4413380482