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Updated: Sep 20, 2025
08:04
Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
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Green's Function Perspective on the Nonlinear Density Response of Quantum Many-Body Systems
Jan Vorberger1, Tobias Dornheim1,2, Maximilian P Böhme3
1Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany.
Journal of Statistical Physics
|May 27, 2025
Summary
This study derives equations for higher-order density response and dielectric functions using thermodynamic Green's functions. These findings advance the understanding of quantum many-body systems under extreme conditions.
Area of Science:
- Theoretical physics
- Condensed matter physics
- Quantum many-body systems
Background:
- Understanding the behavior of quantum many-body systems is crucial for various fields.
- Higher-order response functions are essential for describing complex system dynamics.
- Existing theories may not fully capture the behavior of systems under extreme conditions.
Purpose of the Study:
- To derive equations of motion for higher-order density response functions.
- To obtain expressions for higher-order generalized dielectric and polarization functions.
- To establish relationships between higher-order response functions and collision integrals.
Main Methods:
- Utilizing the theory of thermodynamic Green's functions.
- Applying the Martin-Schwinger hierarchy.
- Developing analytical expressions for complex functions.
Main Results:
- Derived equations of motion for higher-order density response functions.
- Obtained expressions for higher-order generalized dielectric and polarization functions.
- Established a connection between higher-order response functions and collision integrals.
Conclusions:
- The derived equations provide a theoretical framework for analyzing quantum many-body systems.
- Results are expected to be highly relevant for systems under extreme temperatures, densities, and pressures.
- This work contributes to a deeper understanding of fundamental physical phenomena in complex systems.
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