Thermal nonlinear coherent states on a circle

Abstract

In this paper, we construct thermal nonlinear coherent states on the circumference of a circle and demonstrate that these states are fundamentally two-mode squeezed nonlinear coherent states of the circle at absolute zero temperature. Next, we examine the quantum statistical characteristics of states. Specifically, we explore how temperature enhancement influences the transition of the constructed states from nonclassical states to classical, measured by the Mandel parameter, at a so called transition temperature. We show that the amount of the transition temperature is increased by increasing the curvature of the circle. It appears that an increase in spatial curvature enables nonlinear coherent states to retain their nonclassical properties at higher temperature levels. © 2025 Elsevier B.V.