Codes 程式

Below are some toy codes written for education purpose:

Monte Carlo simulation for Ising Model in C++

MC_ising

A second order phase transition shows around temperature T=2.3 at zero field h=0. 

The averaged magnetization<m> change rapidly from <m>~0 to <m>~1, indicating 

the broken symmetry of the Ising spin order.

Real axis Dynamic Mean Field Theory (DMFT) with Iterative Perturbation Theory (IPT) in C++ and openmp

IPT_real_axis

The converged density of state (DOS) at Coulomb U=3 and Temperature T=0.02. The sharp

peak at Fermi energy w=0 is the character of the metal solution. The satellite peaks at w~+/-1

correspond to the lower and upper Hubbard band.

Matsubara axis Dynamic Mean Field Theory (DMFT) with Iterative Perturbation Theory (IPT) in C++

IPT_matsu_axis

Matsubara Green's function for U=1.5(metallic) and U=3.2(insulating) at T=0.01.

Exact Diagonalization for 1D Hubbard (Anderson) chain

Exact Diagonalization(Full version)

Exact Diagonalization(Lanczos version)

Exact diagonalization density of state for 1D Hubbard chain for various coulomb 

interaction. The upper and lower Hubbard band can be seen in the plots.