Energy and entropy flux of the quantum Markovian process through an interacting demon-bit system with squeezed thermal reservoirs

• Main Author: Yang, Guangzhao
• Other Authors: Chew Lock Yue
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Physics; Quantum Markovian master equation; Quantum thermodynamics; Squeezed reservoirs; Interacting information ratchet
• Online Access: https://hdl.handle.net/10356/175665
• Institution: Nanyang Technological University

One of the purposes of the information ratchet, which contains a demon system and bits system, is to mediate the thermodynamics, including energy and entropy flux, between a hot and a cold reservoir. Wherein the demon-bits system is generalized into the quantum regime, therefore demonstrating interesting quantum thermodynamical properties by using the phenomelogical GKSL master equation for the Markovian process. Due to the lack of investigation into the quantum-interacting demon-bits system, reservoirs beyond thermal, and their connection with physical systems, the perturbative Markovian master equation that is obtained by taking the Markovian limit of the exact master equation from the first principles of quantum mechanics is used to formally treat the quantum Markovian dynamics and thermodynamical properties, including energy and entropy flux, with a specific model of the demon-bits system and their interaction with more general reservoirs. We consider a demon-single-bit quantum Heisenberg model interaction that is constructed through electric dipoles and interacts with squeezed thermal reservoirs through a dipole-radiation interaction. Specific models of the dipoles, including identical and nonidentical dipoles, are used to solve the stationary behavior of energy and entropy flux according to the perturbative Markovian master equation analytically with the proper conditions that ensure complete positive trace-preservation and monotonic decreasing of relative entropy. It is shown that the quantum interaction and squeezed thermal reservoirs exhibit complicated influences on the thermodynamics, wherein we show that the squeezing parameters influence the thermodynamics independently from the thermal temperatures, and at a specific amplitude of squeezing, the thermal difference is overcome and therefore reverse the flux (cold to hot through the system); the Heisenberg model interaction of the system renders the system demonstrating significant effects on the thermodynamics, including the initial-state-dependent flux and degeneracy as perfect thermal insulators. Through the formal treatment of quantum systems and reservoirs, we see that the interacting demon-bit system and the squeezing degree-of-freedom in reservoirs affect the thermodynamics significantly. We believe the results obtained draw attention to further investigating the properties of interaction and other achievable reservoirs that imply a wider usage of quantum information ratchet.