Thermal Kosterlitz-Thouless transitions in the $1/r^2$ long-range ferromagnetic quantum Ising chain revisited

TL;DR

This paper investigates the thermal phase transitions in a long-range quantum Ising chain with inverse square interactions, focusing on the Kosterlitz-Thouless phase boundary and effects of quantum fluctuations.

Contribution

It provides a detailed analysis of the thermal phase boundary and critical scaling in the quantum long-range Ising chain, revisiting the classical KT transition in a quantum context.

Findings

The phase boundary of the KT phase is mapped for various transverse fields.

Transverse field causes broadening of specific heat features, indicating smeared domain walls.

Finite-size effects influence the detectability of KT critical scaling.

Abstract

For the inverse square long-range ferromagnetic Ising chain in a transverse field, the thermal phase boundary of the floating Kosterlitz-Thouless phase is obtained for several values of the transverse field down to the quantum critical point. The sharp domain walls in the classical model are increasingly smeared out by the transverse field, which is evidenced by a pronounced broadening of the non-universal bump in the specific heat. The discernability of KT critical scaling in finite-size simulations is discussed.