Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 72: Low-Dimensional Systems: Poster Session

TT 72.21: Poster

Wednesday, March 18, 2015, 15:00–18:00, Poster B

Strongly Degenerate Fermions in 2D Quantum Dots at Finite Temperatures - Configuration Path Integral Monte Carlo — •Simon Groth, Tim Schoof, and Michael Bonitz — Institut for Theoretical and Astrophysics, Christian Albrechts Universität Kiel, Germany

Based on first principles, the configuration PIMC approach (CPIMC) allows for the exact computation of thermodynamic properties of strongly degenerate fermionic many-body systems with arbitrary pair-interaction [1,2]. Due to the fermion sign problem, this regime is not accessible with (standard) PIMC methods. Here, a Worm algorithm within the CPIMC formalism is presented which, in addition to standard thermodynamic observables, is capable of providing exact results for imaginary time correlation functions, i.e., in particular for the Matsubara Green function. The method is tested for a two-dimensional system of spin polarized, Coulomb interacting fermions in a harmonic trap. Further, sampling only paths from a subspace of the whole configuration space (Restricted CPIMC), the sign problem can be circumvented. The introduced systematic error vanishes with increasing degeneracy.

[1] T. Schoof, M. Bonitz, A. Filinov, D. Hochstuhl, and J. Dufty, Contrib. Plasma Phys. 51, 687 (2011).

[2] T. Schoof, S. Groth and M. Bonitz, Introduction to Configuration Path Integral Monte Carlo, Chapter in: Complex Plasmas: Scientific Challenges and Technological Opportunities edited by M. Bonitz, K. Becker, J. Lopez and H. Thomsen (Springer 2014).