Extracting matrix elements of exp(-dt*H_bond)
Posted: 25 Oct 2018, 00:20
Say, I'd like to 'see' the matrix elements tenpy obtains for My question is, if
Thx.
exp(-dt*H_bond)
, in order to compare them with a side-calculation of the same matrix elements without tenpy. What I did was Code: Select all
parm = {'L':2, '...model parms....': ...., 'bc_MPS': 'infinite'}
w = MyMod(parm) # some model I have
psi = MPS.from_product_state(w.lat.mps_sites(), [...some local state...]*parm['L'],parm['bc_MPS'])
# don't care about parameters, except maybe (???) for 'oder' and 'delta_tau_list' (as a side remark, not related to this
post, I cannot find proper docu of 'delta_tau_list'.)
tebd_param = {'order': 1,'delta_tau_list': [1.],'max_error_E': 1.,'trunc_params': {'chi_max':10, 'sdv_min': 1.e-10}}
# set tebd machine and eval U for some crazy dt
eng = tebd.Engine(psi,w,tebd_param)
dt = 1.
eng.calc_U(1,dt,type_evo='imag')
# extract matrix elements of U
m=eng._U[0][0]._data[0]
m
on the last line is indeed exp(-dt*H_bond)
and if not, from where / how I can get it.Thx.