Fermionic Free Energies from Ab Initio Path Integral Monte Carlo Simulations of Fictitious Identical Particles.

Area of Science:

• Computational Physics
• Quantum Many-Body Systems
• Statistical Mechanics

Background:

• The fermion sign problem hinders accurate quantum simulations.
• Calculating free energy for interacting Fermi systems is computationally challenging.

Purpose of the Study:

• To develop a novel computational approach for accurate fermionic free energy calculations.
• To address the fermion sign problem in quantum systems.

Main Methods:

• Combining the η-ensemble path integral Monte Carlo method with a fictitious partition function technique.
• Applying the combined method to the warm, dense, uniform electron gas.

Main Results:

• Accurate exchange-correlation free energy results for the electron gas down to half the Fermi temperature.
• Excellent agreement with existing state-of-the-art parametrizations.
• Demonstrated capability to handle the fermion sign problem.

Conclusions:

• The new method provides a robust framework for fermionic free energy calculations.
• Opens new research avenues for warm dense matter, ultracold atoms, and quantum dots.
• Enables simulations of interacting Fermi systems at unprecedented system sizes.