Spectral density modulation and universal Markovian closure of fermionic environments

Area of Science:

• Quantum Physics
• Computational Chemistry
• Condensed Matter Physics

Background:

• Chain-mapping and tensor-network techniques offer numerically exact simulations of open quantum systems.
• These methods face challenges with quadratic time scaling, especially for multiple or highly correlated fermionic environments.
• Simulating long-time dynamics in such systems is computationally demanding.

Purpose of the Study:

• To develop more efficient simulation methods for open quantum systems with structured environments.
• To address the computational cost associated with fermionic environments and multiple environmental interactions.
• To reduce the time complexity of chain-mapping based algorithms for long-time dynamics.

Main Methods:

• Thermo-chemical modulation of spectral density to simplify fermionic environments.
• Development and application of the fermionic Markovian closure construction.
• Utilizing a reduced set of damped fermionic modes with Lindblad-type dynamics.

Main Results:

• Thermo-chemical modulation successfully replaces complex fermionic environments with simpler, equivalent ones.
• The proposed procedure reduces the number of chains required for modeling multiple environments.
• The fermionic Markovian closure enables a polynomial reduction in time complexity for long-time simulations.

Conclusions:

• The study presents a significant advancement in the efficient simulation of open quantum systems.
• The developed methods offer a computationally tractable approach for handling complex fermionic environments.
• This work paves the way for more extensive studies of quantum dynamics in challenging systems.