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Twin-Space Representation of Classical Mapping Model in the Constraint Phase Space Representation: Numerically Exact
Jiaji Zhang1, Jian Liu2, Lipeng Chen1
1Zhejiang Laboratory, Hangzhou 311100, China.
Journal of Chemical Theory and Computation
|June 26, 2025
Summary
This study introduces an exact phase space method for molecular dynamics, avoiding approximations in condensed-phase simulations. The new approach accurately models open quantum systems, improving upon previous methods.
Area of Science:
- Quantum Chemistry
- Chemical Physics
- Molecular Dynamics
Background:
- Constraint Coordinate-Momentum Phase Space (CPS) is used for nonadiabatic dynamics.
- Previous CPS methods approximated environmental bath degrees of freedom (DOFs).
Purpose of the Study:
- Develop an exact trajectory-based phase space approach for condensed-phase molecular systems.
- Overcome limitations of previous approximate methods in system-bath models.
Main Methods:
- Adopted the twin-space (TS) formulation of quantum statistical mechanics.
- Mapped the expanded system Hamiltonian to a classical counterpart on CPS using the classical mapping model (CMM).
Main Results:
- Simulated population dynamics and nonlinear spectra for benchmark condensed-phase system-bath models.
- Validated the TS-CMM approach against the hierarchical equations of motion method.
Conclusions:
- The developed TS-CMM approach provides an exact trajectory-based phase space method.
- This method accurately describes the dynamics of open quantum systems without approximations.
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