https://doi.org/10.1140/epjp/s13360-020-00919-2
Regular Article
Electron-light interaction in nonequilibrium: exact diagonalization for time-dependent Hubbard Hamiltonians
1
Institute of Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040, Wien, Austria
2
Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040, Wien, Austria
* e-mail: kauch@ifp.tuwien.ac.at
Received:
5
June
2020
Accepted:
4
November
2020
Published online:
19
November
2020
We present a straightforward implementation scheme for solving the time-dependent Schrödinger equation for systems described by the Hubbard Hamiltonian with time-dependent hoppings. The computations can be performed for clusters of up to 14 sites with, in principle, general geometry. For the time evolution, we use the exponential midpoint rule, where the exponentials are computed via a Krylov subspace method, which only uses matrix-vector multiplication. The presented implementation uses standard libraries for constructing sparse matrices and for linear algebra. Therefore, the approach is easy to use on both desktop computers and computational clusters. We apply the method to calculate time evolution of double occupation and nonequilibrium spectral function of a photo-excited Mott-insulator. The results show that not only the double occupation increases due to creation of electron-hole pairs but also the Mott gap becomes partially filled.
© The Author(s), 2020
