Block entropy area based non-local fermionic mode optimization with gradient disentanglers

Abstract:We introduce a systematic block entropy area based mode optimization algorithm for many-body quantum states of interacting fermions represented by matrix product states. From the gradient of a global cost function, the block entropy area, a long-ranged, non-interacting effective disentangler Hamiltonian is formed. We then simulate the time-dependent Schrödinger equation driven by the disentangler Hamiltonian by employing the time-dependent variational principle based on projector splitting, and minimize the cost function. The combination of the density matrix renormalization group with this gradient-based entanglement minimization forms an efficient low-rank iterative ground-state algorithm that also provides an optimized single-particle basis for matrix product state representation. We demonstrate the method on two-dimensional lattice models of interacting fermions and the Fe${_4}$S${_4}$ cluster, and show its robustness and superiority over earlier protocols using nearest-neighbor mode rotations and reorderings.

Strongly Correlated Electrons (cond-mat.str-el); Statistical Mechanics (cond-mat.stat-mech); Computational Physics (physics.comp-ph); Quantum Physics (quant-ph)

arXiv:2609.11811 [cond-mat.str-el]

(or arXiv:2609.11811v1 [cond-mat.str-el] for this version)

https://doi.org/10.48550/arXiv.2609.11811 arXiv-issued DOI via DataCite (pending registration)