Implementation of LDA+DMFT with pseudo-potential-plane-wave method

In this paper, we propose an efficient implementation of combining Dynamical Mean field theory (DMFT) with electronic structure calculation based on the local density approximation (LDA). The pseudo-potential-plane-wave method is used in the LDA part, which makes it possible to be applied to large systems. The full loop self consistency of the charge density has been reached in our implementation which allows us to compute the total energy related properties. The procedure of LDA+DMFT is introduced in detail with a complete flow chart. We have also applied our code to study the electronic structure of several typical strong correlated materials, including Cerium, Americium and NiO. Our results fit quite well with both the experimental data and previous studies.

An Impurity Solver Using the Time-Dependent Variational Matrix Product State Approach

We use the time dependent variational matrix product state (tVMPS) approach to investigate the dynamical properties of the single impurity Anderson model (SIAM). Under the Jordan-Wigner transformation, the SIAM is reformulated into two spin-1/2 XY chains with local magnetic fields along the z-axis. The chains are connected by the longitudinal Ising coupling at the end points. The ground state of the model is searched variationally within the space spanned by the matrix product state (MPS). The temporal Greens functions are calculated both by the imaginary and real time evolutions, from which the spectral information can be extracted. The possibility of using the tVMPS approach as an impurity solver for the dynamical mean field theory is also addressed. Finite temperature density operator is obtained by the ancilla approach. The results are compared to those from the Lanczos and the Hirsch-Fye quantum Monte-Carlo methods.

A Fast Impurity Solver Based on Gutzwiller variational approach

A fast impurity solver for the dynamical mean field theory(DMFT) named Two Mode Approxi- mation (TMA) is proposed based on the Gutzwiller variational approach, which captures the main features of both the coherent and incoherent motion of the electrons. The new solver works with real frequency at zero temperature and it provides directly the spectral function of the electrons. It can be easily generalized to multi-orbital impurity problems with general on-site interactions, which makes it very useful in LDA+DMFT. Benchmarks on one and two band Hubbard models are presented, and the results agree well with those of Exact Diagonalization (ED).