Scaling Relation for Excitation Energy Under Hyperbolic Deformation

TL;DR

This paper introduces a hyperbolic deformation in 1D quantum lattice models, enabling the derivation of scaling relations that facilitate the analysis of excitation gaps in bulk quantum systems.

Contribution

The authors propose a novel hyperbolic deformation method that preserves the ground state and provides a new finite-size scaling approach for excitation energies.

Findings

Derived scaling relations for confinement width and energy correction.

Demonstrated the method's effectiveness in analyzing excitation gaps.

Showed the deformation does not significantly alter the ground state.

Abstract

We introduce a one-parameter deformation for one-dimensional (1D) quantum lattice models, the hyperbolic deformation, where the scale of the local energy is proportional to cosh lambda j at the j-th site. Corresponding to a 2D classical system, the deformation does not strongly modify the ground state. In this situation, the effective Hamiltonian of the quantum system shows that the quasi particle is weakly bounded around the center of the system. By analyzing this binding effect, we derive scaling relations for the mean-square width <w^2> of confinement, the energy correction with respect to the excitation gap \Delta, and the deformation parameter $\lambda$. This finite-size scaling allows us to investigate excitation gap of 1D non-deformed bulk quantum systems.