First order phase transition in the anisotropic quantum orbital compass model

TL;DR

This paper uses tensor network algorithms to study the anisotropic quantum orbital compass model, revealing a first order quantum phase transition at the symmetric point and demonstrating the effectiveness of these methods for such transitions.

Contribution

It provides the first detailed tensor network analysis of the quantum orbital compass model, confirming the first order phase transition and showcasing the method's suitability.

Findings

Identification of a first order quantum phase transition at J_x=J_z.

Coexistence of multiple ground states with different local properties.

Tensor network algorithms effectively characterize first order transitions.

Abstract

We investigate the anisotropic quantum orbital compass model on an infinite square lattice by means of the infinite projected entangled-pair state algorithm. For varying values of the $J_x$ and $J_z$ coupling constants of the model, we approximate the ground state and evaluate quantities such as its expected energy and local order parameters. We also compute adiabatic time evolutions of the ground state, and show that several ground states with different local properties coexist at $J_x = J_z$. All our calculations are fully consistent with a first order quantum phase transition at this point, thus corroborating previous numerical evidence. Our results also suggest that tensor network algorithms are particularly fitted to characterize first order quantum phase transitions.