A Spectrally Accurate Numerical Method for Computing the Bogoliubov--de Gennes Excitations of Dipolar Bose--Einstein Condensates
Qinglin Tang, Manting Xie, Yong Zhang +1 more
In this paper, we propose an efficient and robust numerical method to study the elementary excitation of dipolar Bose--Einstein condensates, which is governed by the Bogoliubov--de Gennes equations (BdGEs) with nonlocal dipole-dipole interaction, around the mean field ground state. Analytical properties of the BdGEs are investigated, which could serve as benchmarks for the numerical methods. To evaluate the nonlocal interactions accurately and efficiently, we propose a new simple Fourier spectral convolution (SFSC) method. Then, integrating SFSC with the standard Fourier spectral method for spatial discretization and implicitly restarted Arnoldi methods (IRAM) for the eigenvalue problem, we derive an efficient and spectrally accurate method, named the SFSC-IRAM, for the BdGEs. Ample numerical tests are provided to illustrate the accuracy and efficiency. Finally, we apply the new method to study systematically the excitation spectrum and Bogoliubov amplitudes around the ground state with different parameters in different spatial dimensions.
SIAM Journal on Scientific Computing•Jan 18, 2022•4 citations