Hi All
I am trying to implement iDMRG using iTensor. My code roughly follows (though it is a 2D version) this Mueller: Basic Training 2019
And I am trying to benchmark my performance by solving the transverse field ising model, and I am trying to reproduce the results in this paper (Fig1), Dynamical phase transitions in the two-dimensional transverse-field Ising model. The Hamiltonian is
H=\sum_{<i,j>}-J\sigma^z_i\sigma^z_j-\sum_i h\sigma^x_i
My problem is that the iteration becomes super slow near the critical point. I am using a cylidrical geometry with width w.
For example, for width w=2, h=2.3J, it takes around an hour to converge (around 3-400 iterations).
For w=4, h=2.6/2.7J, I never get through the first few iterations within two hours (by iterations, I mean inserting sites).
For reference, I am setting my maximum bond dimension to be 2000, and the SVD cutoff to be 10^(-10).
My question it: for those of you who have either implemented iDMRG using ITensor, or those doing TenPy, what amount of time should I expect points near critical point? Do you have a benchmark results I can calibrate to?
Thanks a lot!