Large-n excitations in the ferromagnetic Ising field theory in a small magnetic field: mass spectrum and decay widths

TL;DR

This paper investigates the mass spectrum and decay widths of large-n excitations in the ferromagnetic Ising model under a small magnetic field, providing perturbative results for high-n states and their stability properties.

Contribution

It introduces a perturbative approach to compute the mass spectrum and decay widths of large-n excitations in the Ising model with a small magnetic field.

Findings

Mass spectrum for large-n excitations derived in first-order perturbation.

Decay widths for unstable excitations calculated at leading order.

Results enhance understanding of excitation stability in the ferromagnetic phase.

Abstract

In presence of a small magnetic field h, the elementary excitations in the scaling two-dimensional Ising model are studied perturbatively in h in the ferromagnetic phase. For excitations with large numbers n, the mass spectrum is obtained in the first order in h. The decay widths of excitations with energies above the stability threshold are calculated in the leading h^3-order.