An improvement of the filter diagonalization-based post-processing method applied to finite difference time domain calculations of three-dimensional phononic band structures

Abstract

When three-dimensional (3D) phononic band structures are calculated by using the finite difference time domain (FDTD) method with a relatively small number of iterations, the results can be effectively improved by post-processing the FDTD time series (FDTD-TS) based on the filter diagonalization method (FDM), instead of the classical fast Fourier transform. In this paper, we propose a way to further improve the performance of the FDM-based post-processing method by introducing a relatively large number of observing points to record the FDTD-TS. To this end, the existing scheme of FDTD-TS preprocessing is modified. With the new preprocessing scheme, the processing efficiency of a single FDTD-TS can be improved significantly, and thus the entire post-processing method can have sufficiently high efficiency even when a relatively large number of observing points are used. The feasibility of the proposed method for improvement is verified by the numerical results.

Delaying disappearance of entanglement by the linear modulation of atom-field coupling

“…It should be noted that, in recent years, many efforts have been invested in the study of the entanglement of noninteracting qubits [16][17][18][19][20][21][22][23], because this non-local state behavior can be used to simulate that of qubit pairs in remotely located networks. Two qubits can be located anywhere in a large network, so their entanglement is an important issue.…”