Achieving the Scaling Limit for Nonequilibrium Green Functions Simulations.

Area of Science:

• Quantum Dynamics
• Condensed Matter Physics
• Strongly Correlated Fermions

Background:

• Strongly correlated fermions exhibit complex quantum phenomena under external excitation.
• Nonequilibrium Green functions (NEGF) is the standard method for simulating these dynamics in 2D and 3D.
• Standard NEGF simulations have a high computational cost, scaling as T^3 with simulation time T.

Purpose of the Study:

• To develop a more computationally efficient method for simulating quantum dynamics of strongly correlated fermions.
• To reduce the computational scaling of NEGF simulations.

Main Methods:

• The study utilizes the generalized Kadanoff-Baym ansatz (GKBA) combined with NEGF.
• The research focuses on achieving a T^1 scaling for both second-order Born (SOA) and GW selfenergies.
• This approach optimizes the computational performance of NEGF simulations.

Main Results:

• Demonstrated that GKBA-NEGF simulations can achieve a linear T^1 scaling.
• This T^1 scaling is valid for both SOA and GW selfenergies.
• The optimized method significantly enhances the scope and feasibility of NEGF simulations.

Conclusions:

• The developed T^1 scaling GKBA-NEGF method offers a computationally efficient approach for quantum dynamics.
• This advancement substantially extends the capabilities for studying complex fermionic systems.
• The approach highlights remarkable potential for future research in correlated quantum phenomena.