1;

Nlevels=4;
w_hpf_ground=6834;
w_hpf_exited=817;
w_pf1=1e9; % largest transition frequency
w1=w_pf1;
w2=0;
w3=w_hpf_ground;
w4=w_hpf_ground+.1; % separation of levels |3> and |4> somewhat like Zeeman splitting
w12=w1-w2;
w13=w1-w3;

%
%      -----------  |1>
%         /     \
%    E_d /       \ 
%       /         \ E_p
%      /           \
%    -------- |3>   \
%    --------   |4>  \
%                     \
%               ___________ |2>


% unperturbed Hamiltonian energy levels
levels_energy=[ w1, 0,  w3, w4];
levels_energy=levels_energy*hbar;
H0=zeros(Nlevels);
H0=diag(levels_energy);
%for i=1:Nlevels
	%H0(i,i)=levels_energy(i);
%endfor

% decay matrix g(i,j) correspnds to decay from i-->j
gamma=6;
gamma_23=.001;
g_decay=zeros(Nlevels);
g_decay(1,2)=gamma; %upper level decay
g_decay(1,3)=gamma; %upper level decay
g_decay(1,4)=gamma; %upper level decay
g_decay(3,2)=gamma_23; % lower levels mixing
g_decay(2,3)=gamma_23; % lower levels mixing
g_decay(4,2)=gamma_23; % lower levels mixing
g_decay(2,4)=gamma_23; % lower levels mixing


% dipole matrix
dipole_elements.left=zeros(Nlevels);
dipole_elements.left(1,2)=1;
dipole_elements.left(2,1)=dipole_elements.left(1,2);
dipole_elements.left(1,3)=0;
dipole_elements.left(3,1)=dipole_elements.left(1,3);
dipole_elements.left(1,4)=0;
dipole_elements.left(4,1)=dipole_elements.left(1,4);

dipole_elements.right=zeros(Nlevels);
dipole_elements.right(1,2)=0;
dipole_elements.right(2,1)=dipole_elements.right(1,2);
dipole_elements.right(1,3)=1;
dipole_elements.right(3,1)=dipole_elements.right(1,3);
dipole_elements.right(1,4)=1;
dipole_elements.right(4,1)=dipole_elements.right(1,4);

dipole_elements.linear=zeros(Nlevels);
dipole_elements.linear(1,2)=0;
dipole_elements.linear(2,1)=dipole_elements.linear(1,2);
dipole_elements.linear(1,3)=0;
dipole_elements.linear(3,1)=dipole_elements.linear(1,3);
dipole_elements.linear(1,4)=0;
dipole_elements.linear(4,1)=dipole_elements.linear(1,4);

maximum_dipole_elements=dipole_elements.linear + dipole_elements.left + dipole_elements.right;

%defasing matrix
g_deph=0;
g_dephasing=zeros(Nlevels);
% dephasing only for non zero dipole elements (am I right?)
g_dephasing=g_deph*(maximum_dipole_elements != 0);