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Solving the Kadanoff-Baym equations for inhomogeneous systems: application to atoms and molecules
Nils Erik Dahlen1, Robert van Leeuwen
1Theoretical Chemistry, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Physical Review Letters
|May 16, 2007
Summary
We present a time-propagation method for nonequilibrium Green functions, enabling accurate calculations of spectral functions and electron dynamics under electric fields. This approach also determines excitation energies, matching advanced Bethe-Salpeter equation solutions.
Area of Science:
- Quantum mechanics
- Condensed matter physics
- Computational chemistry
Background:
- The Kadanoff-Baym equations are crucial for describing quantum dynamics.
- Nonequilibrium Green functions (NEGF) are essential for studying systems out of equilibrium.
- Accurate calculation of spectral functions and excitation energies is vital in many-body physics.
Purpose of the Study:
- To implement time propagation of NEGF for atoms and molecules.
- To demonstrate the method's utility for spectral functions and correlated electron dynamics.
- To showcase its capability in calculating charge-neutral excitation energies.
Main Methods:
- Solving Kadanoff-Baym equations.
- Utilizing a conserving self-energy approximation.
- Employing time propagation for NEGF.
Main Results:
- Successfully implemented time-dependent NEGF calculations.
- Demonstrated accurate spectral function calculations.
- Described nonperturbative electron dynamics in electric fields.
- Calculated charge-neutral excitation energies comparable to Bethe-Salpeter equation solutions.
Conclusions:
- Time propagation of NEGF is a powerful tool for quantum dynamics.
- The method provides accurate spectral and excitation energy data.
- It offers a nonperturbative approach to studying electron correlations.
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