Reduced dynamical maps in finite temperature vibronic coupling models via Choi matrices: Numerical methods and
Raffaele Borrelli1, Hideaki Takahashi1
1DISAFA, University of Torino, Torino, Italy.
The Journal of Chemical Physics
|June 8, 2026
Summary
We developed a computational method to analyze quantum dynamics in complex systems. This framework efficiently models thermal environments and system-bath interactions for accurate predictions.
Area of Science:
- Quantum Dynamics
- Computational Chemistry
- Condensed Matter Physics
Background:
- Modeling complex quantum systems requires efficient methods to handle thermal environments.
- Reduced dynamical maps are crucial for understanding system-bath interactions.
- Existing methods can be computationally intensive for finite-temperature systems.
Purpose of the Study:
- To present a streamlined computational framework for constructing and analyzing reduced dynamical maps.
- To enable efficient analysis of complex system-bath models at finite temperatures.
- To provide a route for computing reduced propagators and related kinetic descriptions.
Main Methods:
- Utilizing Choi-Jamiołkowski isomorphism for quantum channel representation.
- Employing thermofield (TFD) purification for thermal environments.
- Implementing tensor-train (TT) propagation for high-dimensional purified thermal states.
Main Results:
- A single unitary propagation in a thermofield-doubled Hilbert space yields the reduced map.
- Efficient propagation of high-dimensional thermal states is achieved via TT representation.
- The methodology was illustrated for exciton transfer in the Fenna-Matthews-Olson complex.
Conclusions:
- The framework provides an efficient route to compute reduced propagators for complex molecular systems.
- The method allows for analysis of decoherence, relaxation, and finite-memory effects.
- It facilitates the assessment of crossovers to time-local descriptions.
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