Nonequilibrium Steady-State Transport in Quantum Impurity Models: A Thermofield and Quantum Quench Approach Using...

Area of Science:

• Quantum Many-Body Physics
• Condensed Matter Theory
• Computational Physics

Background:

• Numerical Renormalization Group (NRG) is effective for equilibrium quantum impurity models.
• Standard NRG struggles with steady-state nonequilibrium phenomena, such as those induced by bias voltage.
• Accurate simulation of interacting quantum impurity models in nonequilibrium is crucial for understanding transport properties.

Purpose of the Study:

• To overcome limitations of NRG for steady-state nonequilibrium transport in quantum impurity models.
• To develop a hybrid computational approach combining NRG and TDMRG for reliable simulations.
• To accurately calculate transport properties, like electrical current, in nonequilibrium regimes.

Main Methods:

• Utilized a thermofield approach to describe thermal leads.
• Integrated out high-energy modes using NRG.
• Treated low-energy nonequilibrium dynamics via a quench protocol implemented with time-dependent density matrix renormalization group (TDMRG).

Main Results:

• Achieved quantitatively reliable current calculations with errors below 3%.
• Successfully simulated exponentially small energy scales characteristic of impurity models.
• Presented benchmark results for the temperature and magnetic field dependence of the zero-bias conductance peak in the single-impurity Anderson model.

Conclusions:

• The hybrid NRG-TDMRG approach effectively addresses limitations of NRG for steady-state nonequilibrium transport.
• This method enables highly accurate simulations of quantum impurity models at small energy scales.
• The findings provide benchmark data for the single-impurity Anderson model, advancing the understanding of quantum transport.