Self-congruent point in critical matrix product states: An effective field theory for finite-entanglement scaling

Fuente: arXiv
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Main Authors: Schneider, Jan T., Ueda, Atsushi, Liu, Yifan, Läuchli, Andreas M., Oshikawa, Masaki, Tagliacozzo, Luca
Format: Preprint
Published: 2024
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author Schneider, Jan T.
Ueda, Atsushi
Liu, Yifan
Läuchli, Andreas M.
Oshikawa, Masaki
Tagliacozzo, Luca
author_facet Schneider, Jan T.
Ueda, Atsushi
Liu, Yifan
Läuchli, Andreas M.
Oshikawa, Masaki
Tagliacozzo, Luca
contents We set up an effective field theory formulation for the renormalization flow of matrix product states (MPS) with finite bond dimension, focusing on systems exhibiting finite-entanglement scaling close to a conformally invariant critical fixed point. We show that the finite MPS bond dimension $χ$ is equivalent to introducing a perturbation by a relevant operator to the fixed-point Hamiltonian. The fingerprint of this mechanism is encoded in the $χ$-independent universal transfer matrix's gap ratios, which are distinct from those predicted by the unperturbed Conformal Field Theory. This phenomenon defines a renormalization group self-congruent point, where the relevant coupling constant ceases to flow due to a balance of two effects; When increasing $χ$, the infrared scale, set by the correlation length $ξ(χ)$, increases, while the strength of the perturbation at the lattice scale decreases. The presence of a self-congruent point does not alter the validity of the finite-entanglement scaling hypothesis, since the self-congruent point is located at a finite distance from the critical fixed point, well inside the scaling regime of the CFT. We corroborate this framework with numerical evidences from the exact solution of the Ising model and density matrix renormalization group (DMRG) simulations of an effective lattice model.
format Preprint
id arxiv_https___arxiv_org_abs_2411_03954
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Self-congruent point in critical matrix product states: An effective field theory for finite-entanglement scaling
Schneider, Jan T.
Ueda, Atsushi
Liu, Yifan
Läuchli, Andreas M.
Oshikawa, Masaki
Tagliacozzo, Luca
Statistical Mechanics
High Energy Physics - Theory
Quantum Physics
We set up an effective field theory formulation for the renormalization flow of matrix product states (MPS) with finite bond dimension, focusing on systems exhibiting finite-entanglement scaling close to a conformally invariant critical fixed point. We show that the finite MPS bond dimension $χ$ is equivalent to introducing a perturbation by a relevant operator to the fixed-point Hamiltonian. The fingerprint of this mechanism is encoded in the $χ$-independent universal transfer matrix's gap ratios, which are distinct from those predicted by the unperturbed Conformal Field Theory. This phenomenon defines a renormalization group self-congruent point, where the relevant coupling constant ceases to flow due to a balance of two effects; When increasing $χ$, the infrared scale, set by the correlation length $ξ(χ)$, increases, while the strength of the perturbation at the lattice scale decreases. The presence of a self-congruent point does not alter the validity of the finite-entanglement scaling hypothesis, since the self-congruent point is located at a finite distance from the critical fixed point, well inside the scaling regime of the CFT. We corroborate this framework with numerical evidences from the exact solution of the Ising model and density matrix renormalization group (DMRG) simulations of an effective lattice model.
title Self-congruent point in critical matrix product states: An effective field theory for finite-entanglement scaling
topic Statistical Mechanics
High Energy Physics - Theory
Quantum Physics
url https://arxiv.org/abs/2411.03954