The Master Equation for Two-Level Accelerated Systems at Finite Temperature

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• 作者：J. L. Tomazelli ; R. O. Cunha
• 关键词：Unruh effect ; Thermo field dynamics ; Quantum field theory ; Master equation
• 刊名：Brazilian Journal of Physics
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：46
• 期：5
• 页码：503-515
• 全文大小：634 KB
• 刊物类别：Physics and Astronomy
• 出版者：Springer New York
• ISSN：1678-4448
• 卷排序：46

文摘

In this work, we study the behaviour of two weakly coupled quantum systems, described by a separable density operator; one of them is a single oscillator, representing a microscopic system, while the other is a set of oscillators which perform the role of a reservoir in thermal equilibrium. From the Liouville-Von Neumann equation for the reduced density operator, we devise the master equation that governs the evolution of the microscopic system, incorporating the effects of temperature via Thermofield Dynamics formalism by suitably redefining the vacuum of the macroscopic system. As applications, we initially investigate the behaviour of a Fermi oscillator in the presence of a heat bath consisting of a set of Fermi oscillators and that of an atomic two-level system interacting with a scalar radiation field, considered as a reservoir, by constructing the corresponding master equation which governs the time evolution of both sub-systems at finite temperature. Finally, we calculate the energy variation rates for the atom and the field, as well as the atomic population levels, both in the inertial case and at constant proper acceleration, considering the two-level system as a prototype of an Unruh detector, for admissible couplings of the radiation field.