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Quantum thermodynamics of single particle systems
Md Manirul Ali1, Wei-Ming Huang1, Wei-Min Zhang2
1Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan.
Scientific Reports
|August 13, 2020
Summary
We developed a new quantum thermodynamics theory for small systems, showing how thermodynamics emerges from quantum dynamics without assuming equilibrium. This theory reveals dynamical quantum phase transitions and proves the third law of thermodynamics.
Area of Science:
- Quantum mechanics
- Statistical mechanics
- Thermodynamics
Background:
- Classical thermodynamics relies on equilibrium states, but its emergence from quantum mechanics is unclear.
- Understanding quantum thermodynamics in small systems is crucial for bridging quantum dynamics and macroscopic thermodynamic laws.
Purpose of the Study:
- To develop a theory of quantum thermodynamics applicable to arbitrary small systems, including single particles coupled to a reservoir.
- To generalize the concept of temperature beyond equilibrium, incorporating quantum state dynamics.
- To investigate the emergence and breakdown of thermodynamics in various coupling regimes and explore dynamical quantum phase transitions.
Main Methods:
- Developing a generalized quantum thermodynamics theory for small systems.
- Analyzing systems (cavity, two-level) coupled to a reservoir.
- Examining weak and intermediate system-reservoir coupling regimes, including breakdown of Born-Markovian approximation.
- Investigating non-Markovian memory effects and localized bound states.
Main Results:
- Thermodynamics emerges naturally from exact quantum dynamics in the weak coupling regime without prior equilibrium assumptions.
- Thermodynamics emerges even in the intermediate coupling regime where the Born-Markovian approximation fails.
- Thermodynamics breaks down due to non-Markovian memory effects from localized bound states.
- A dynamical quantum phase transition with inflationary dynamics and negative dynamical temperature was identified.
Conclusions:
- The theory provides a framework for understanding thermodynamics in small quantum systems.
- Dynamical criticality separates classical and quantum realms, with implications for cosmology.
- The third law of thermodynamics is naturally proven within this quantum framework.
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