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TT: Fachverband Tiefe Temperaturen

TT 37: Correlated Electrons: Poster

TT 37.55: Poster

Mittwoch, 19. März 2025, 15:00–18:00, P4

Traces of powers of many-body Hamiltonians — •Marcus Kollar — Theoretische Physik III, University of Augsburg

The high-temperature expansion of the partition function for a many-body system of fermions or bosons involves Fock space traces of powers of the Hamiltonian. Here we use algebraic means to evaluate such moments for a fixed number of non-interacting particles with arbitrary discrete spectrum and express them as polynomials of power sums of the single-particle energies. In the fermionic case our expressions agree with those obtained by combinatorial considerations [1]. We discuss possible applications and generalizations of our results.
[1] E. Adibi and E. Koch, Verhandl. DPG, Berlin TT 80.44 (2024).

Keywords: Fock space; partition function; high-temperature expansion