Hi Abbout,
Thanks for pointing out the mistakes that I was making. Now, I want to
implement a formula like the one mentioned in the thread before to calculate
the equilibrium dc current for a Josephson junction:
I = 2*(KbT/hbar)/sum_{w_p} [trace(H21*G^R_{12}) - trace(H12*G^R_{21})
where w_p are the Matsubara frequencies.
I wrote the following to get the green's functions:
_______________________________________________________________
def mount_vlead(sys, vlead_interface, norb):
dim = norb*len(vlead_interface)
print(dim)
zero_array = np.zeros((dim, dim), dtype=float)
def selfenergy_func(energy, args=()):
return zero_array
vlead = kwant.builder.SelfEnergyLead(selfenergy_func, vlead_interface,())
sys.leads.append(vlead)
lead2 = mount_vlead(syst,[lat(L-1)], 2)
lead3 = mount_vlead(syst,[lat(L)], 2)
syst =syst.finalized()
G12=kwant.greens_function(syst, energy=-1.8*1j, in_leads=[2],out_leads=[3],\
check_hermiticity=False,params=par).data
G21=kwant.greens_function(syst, energy=-1.8*1j, in_leads=[3],out_leads=[2],\
check_hermiticity=False,params=par).data
H12=syst.hamiltonian_submatrix(to_sites=[L-1], from_sites=[L],params=par)
H21=syst.hamiltonian_submatrix(to_sites=[L], from_sites=[L-1],params=par)
So my question is now, that if the Green's functions that I am using above are
truly the retarded Green's function of the system?
Thanks,
Sayandip
