Anomalous Flux Quantization in the Spin-Imbalanced Attractive Hubbard Ring

作者：Sano Kazuhiro^*; Ono Yoshiaki

来源：Journal of the Physical Society of Japan, 2013, 82(5): 054707.

DOI：10.7566/JPSJ.82.054707

• FFLO state
• flux quantization
• spin imbalance
• attractive Hubbard model
• exact diagonalization

We investigate the one-dimensional Hubbard ring with attractive interaction in the presence of imbalanced spin populations by using the exact diagonalization method. The singlet pairing correlation function is found to show spatial oscillations with power-law decay as expected in the Fulde-Ferrell-Larkin-Ovchinnikov state of a Tomonaga-Luttinger liquid. In the strong coupling regime, the system shows an anomalous flux quantization of period h/4e, half of the superconducting flux quantum of h/2e, as recently predicted by mean-field analysis, together with various flux quanta smaller than h/4e. Notably, the observed flux quanta are determined by the difference between the system size N-L and electron number N-e as h/(N-L - N-e)e.

• 出版日期2013-5