Finite-size scaling at first-order quantum transitions when boundary conditions favor one of the two phases

TL;DR

This paper studies how boundary conditions that favor one phase affect finite-size scaling at first-order quantum transitions, revealing more complex behaviors than in unbiased boundary conditions, using the quantum Ising model as a case study.

Contribution

It demonstrates the impact of boundary conditions on finite-size scaling at first-order quantum transitions, providing new insights into the interplay between boundary effects and critical phenomena.

Findings

Boundary conditions favoring one phase alter scaling behavior.

Finite-size effects are more complex with biased boundary conditions.

Analysis conducted on the quantum Ising model at its first-order transition line.

Abstract

We investigate scaling phenomena at first-order quantum transitions, when the boundary conditions favor one of the two phases. We show that the corresponding finite-size scaling behavior, arising from the interplay between the driving parameter and the finite size of the system, is more complex than that emerging when boundary conditions do not favor any phase. We discuss this issue in the framework of the paradigmatic one-dimensional quantum Ising model, along its first-order quantum transition line driven by an external longitudinal field.