Auxiliary Master Equation for Nonequilibrium Dual-Fermion Approach

Area of Science:

• Quantum physics
• Condensed matter theory
• Computational physics

Background:

• Correlated impurity models are crucial for understanding complex quantum phenomena.
• Existing dual fermion methods face challenges in accurately describing non-equilibrium steady states.
• Efficient numerical methods are needed for simulating these systems.

Purpose of the Study:

• To introduce a novel auxiliary quantum master equation dual fermion method.
• To demonstrate its convenience and accuracy for steady-state properties of correlated impurity models.
• To provide a computationally efficient alternative to existing formulations.

Main Methods:

• Development of an auxiliary quantum master equation dual fermion approach.
• Formulation of an expansion around a reference state closer to the true non-equilibrium state.
• Application to the Anderson impurity model for validation.

Main Results:

• The proposed method offers a more convenient description of steady states.
• The scheme provides an expansion closer to the true non-equilibrium state.
• Numerical tests on the Anderson impurity model show excellent agreement with exact benchmarks.

Conclusions:

• The auxiliary quantum master equation dual fermion method is a powerful tool for steady-state calculations.
• The approach is numerically inexpensive and avoids time propagation for steady-state problems.
• This method significantly advances the simulation of correlated quantum impurity systems.