DMRG3S

DMRG3S is a DMRG solver implementing a variant of strictly single-site DMRG with subspace expansion [1], combined with a randomized SVD strategy [3], and fully based on ITensorMPS.jl.

Related approaches also include the Controlled Bond Expansion (CBE) algorithm [2,4,5].

The code has only been tested for limited cases. Please use it with caution and validate results carefully.

Example

Spinfull free Fermion on $(N_x,N_y)=(10,4)$ clylinder at filling $N=0.9N_xN_y$ with $U(1)_s\times U(1)_s$ symmetries. See the directory example/square for detailed scripts and parameters.

Energy vs. discarded weight:

Energy vs. square of inverse bond dimension:

Reference

[1]Strictly single-site DMRG algorithm with subspace expansion

[2]Controlled Bond Expansion for Density Matrix Renormalization Group Ground State Search at Single-Site Costs

[3]Comment on "Controlled Bond Expansion for Density Matrix Renormalization Group Ground State Search at Single-Site Costs"

[4]Reply to comment on "Controlled bond expansion for Density Matrix Renormalization Group ground state search at single-site costs"

[5]CBEAlgorithms