Eur. Phys. J. Plus (2021) 136: 444
https://doi.org/10.1140/epjp/s13360-021-01443-7

Regular Article

Effect of thermal noise on the nonclassicality of SU(1, 1) and SU(2) coherent states

¹ Department of Photonics, Graduate University of Advanced Technology, Kerman, Iran
² Department of Physics, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran

^b mj.faghihi@kgut.ac.ir

Received: 29 June 2020
Accepted: 16 April 2021
Published online: 25 April 2021

Abstract

The effects of thermal noise on quantum systems are often unavoidable at finite temperatures and should be taken into account, in order to get consistent results with experimental data. By focusing on the quantum states of light, this effect has been less considered, particulary in the context of generalized coherent states. So, in this paper, we aim to define quantum states which are generated by SU(1, 1) and SU(2) coherent states in the presence of the thermal noise. Indeed, we introduce the quantum states of light which are composed of thermal states and SU(1, 1) (or SU(2)) coherent states. In other words, we establish a connection between displaced thermal states and the SU(1, 1) and SU(2) Lie groups. Afterward, the nonclassicality of the obtained states is examined to understand the role of thermal noise in physical properties such as sub-Poissonian statistics, quadrature squeezing and Wigner–Weyl quasi-probability distribution function. This goal is achieved by changing the temperature of thermal equilibrium. Interestingly, the numerical results indicate that the nonclassicality of the system can be improved by considering the thermal noise.