ORIGINAL RESEARCH article
Front. Phys.
Sec. Condensed Matter Physics
Volume 13 - 2025 | doi: 10.3389/fphy.2025.1569310
Temperature-dependent pure state for the thermodynamic system and its heat reservoir
Provisionally accepted
- School of Science, Dalian Maritime University, Dalian, China
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Based on the quantum Liouville equation and the Lindblad equation, a temperature-dependent pure state was constructed for the composite isolated system consisting of a thermodynamic system and its heat reservoir. The results demonstrate that the expectation value of this pure state coincides with the statistical average of the thermodynamic system's mixed state. Furthermore, the existence of this pure state is consistent with the eigenstate thermalization hypothesis.Additionally, the "fictitious system" introduced in thermo field dynamics can be naturally interpreted as the heat reservoir of the system, and this interpretation allows us to re-examine the relationship between the physical system and the so-called "fictitious system".
Keywords: composite isolated system, pure state, mixed state, Expectation value, Statistical average, thermo field dynamics
Received: 31 Jan 2025; Accepted: 21 Apr 2025.
Copyright: © 2025 Guo, Zhang, Mi and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dong Mi, School of Science, Dalian Maritime University, Dalian, China
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