NESSi  v1.0.1
The NonEquilibrium Systems Simulation Library

◆ green_from_H() [1/6]

template<typename T >
void cntr::green_from_H ( herm_matrix< T > &  G,
mu,
cdmatrix &  eps,
beta,
h 
)

Propagator for time-independent free Hamiltonian

Purpose

Calculate the free propagator G from fixed quadratic Hamiltonian using high-order commutator-free exponential time-propagation, see https://doi.org/10.1016/j.jcp.2011.04.006 for the description. Currently implemented versions are the second order using one exponential CF2:1 (order=2) and fourth order using two exponentials CF4:2 (order=4), see also article for more details.

Parameters
G

The output Greens function set to time dependent free propagator

mu

chemical potential

eps

time-independent representation of quadratical hamiltonian

beta

inverse temperature

h

timestep

Definition at line 1132 of file cntr_equilibrium_impl.hpp.

References cntr::herm_matrix< T >::size1().

1132  {
1133  assert(G.size1()==eps.rows());
1134  assert(eps.rows()==eps.cols());
1135 
1136  int size=G.size1();
1137  if(size==1) green_from_H_const_dispatch<T,1>(G,mu,eps,beta,h);
1138  else green_from_H_const_dispatch<T,LARGESIZE>(G,mu,eps,beta,h);
1139 }
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