Heidelberg 2022 – scientific programme

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MP: Fachverband Theoretische und Mathematische Grundlagen der Physik

MP 4: Quantum field theory, AdS/CFT, non-equilibrium and quantum dynamics

MP 4.3: Talk

Tuesday, March 22, 2022, 16:55–17:15, MP-H5

The free energy of the two-dimensional dilute Bose gas — •Andreas Deuchert¹, Simon Mayer², and Robert Seiringer² — ¹Institute of Mathematics, University of Zurich — ²Institute of Science and Technology Austria (IST Austria)

We prove bounds for the specific free energy of the two-dimensional Bose gas in the thermodynamic limit. We show that the free energy at density ϱ and inverse temperature β differs from the one of the non-interacting system by the correction term 4 π ϱ² | ln(a² ϱ) |⁻¹ (2 − [ 1 −β_c / β ]₊² ) . Here a is the scattering length of the interaction potential, [x]₊ = max(0,x ) and β _c is the inverse Berezinskii–Kosterlitz–Thouless critical temperature for superfluidity. The result is valid in the dilute limit a² ϱ ≪ 1 and if β ϱ 1.