Fermion sign problem in path integral Monte Carlo simulations: grand-canonical ensemble

Abstract We present a practical analysis of the fermion sign problem in fermionic path integral Monte Carlo (PIMC) simulations grand-canonical ensemble (GCE). As representative model system, we consider electrons 2D harmonic trap. find that GCE is even more severe than canonical at same conditions, which, general, makes latter preferred option. Despite these difficulties, show PIMC are still feasible many cases, which potentially gives access to important quantities like compressibility or Matsubara Greens function. This has implications for contemporary fields research such as warm dense matter, ultracold atoms, and quantum dots.