On iterative path integral calculations for a system interacting with a shifted dissipative bath

Area of Science:

• Quantum dynamics
• Computational chemistry
• Condensed matter physics

Background:

• Real-time path integral calculations are crucial for simulating quantum systems.
• The iterative quasi-adiabatic propagator path integral (i-QuAPI) is a common methodology.
• Applying i-QuAPI to systems in dissipative environments presents challenges.

Purpose of the Study:

• To compare two distinct approaches for applying the i-QuAPI methodology.
• To evaluate the efficiency and convergence of each method.
• To identify the most suitable approach for charge transfer simulations.

Main Methods:

• Implementation of i-QuAPI with phase modification via time-local integrals.
• Implementation of i-QuAPI with system coordinate shifting.
• Analysis of convergence properties and computational efficiency.

Main Results:

• Phase modification requires careful memory truncation for convergence.
• Coordinate shifting offers a simpler alternative without modifying the core i-QuAPI algorithm.
• Both methods were applied to a system initially in equilibrium with a harmonic dissipative bath.

Conclusions:

• Coordinate shifting is a more straightforward and potentially efficient approach for applying i-QuAPI.
• This simplification can aid in the real-time simulation of quantum dynamics in dissipative environments.
• Further investigation into the general applicability of coordinate shifting is warranted.