THE FREE ENERGY OF THE TWO-DIMENSIONAL DILUTE BOSE GAS. I. LOWER BOUND

We prove a lower bound for the free energy (per unit volume) of the two-dimensional Bose gas in the thermodynamic limit. We show that the free energy at density $\unicode[STIX]{x1D70C}$ and inverse temperature $\unicode[STIX]{x1D6FD}$ differs from the one of the noninteracting system by the correct...

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Main Authors: ANDREAS DEUCHERT, SIMON MAYER, ROBERT SEIRINGER
Format: Article
Language:English
Published: Cambridge University Press 2020-01-01
Series:Forum of Mathematics, Sigma
Subjects:
Online Access:https://www.cambridge.org/core/product/identifier/S2050509420000171/type/journal_article
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author ANDREAS DEUCHERT
SIMON MAYER
ROBERT SEIRINGER
author_facet ANDREAS DEUCHERT
SIMON MAYER
ROBERT SEIRINGER
author_sort ANDREAS DEUCHERT
collection DOAJ
description We prove a lower bound for the free energy (per unit volume) of the two-dimensional Bose gas in the thermodynamic limit. We show that the free energy at density $\unicode[STIX]{x1D70C}$ and inverse temperature $\unicode[STIX]{x1D6FD}$ differs from the one of the noninteracting system by the correction term $4\unicode[STIX]{x1D70B}\unicode[STIX]{x1D70C}^{2}|\ln \,a^{2}\unicode[STIX]{x1D70C}|^{-1}(2-[1-\unicode[STIX]{x1D6FD}_{\text{c}}/\unicode[STIX]{x1D6FD}]_{+}^{2})$. Here, $a$ is the scattering length of the interaction potential, $[\cdot ]_{+}=\max \{0,\cdot \}$ and $\unicode[STIX]{x1D6FD}_{\text{c}}$ is the inverse Berezinskii–Kosterlitz–Thouless critical temperature for superfluidity. The result is valid in the dilute limit $a^{2}\unicode[STIX]{x1D70C}\ll 1$ and if $\unicode[STIX]{x1D6FD}\unicode[STIX]{x1D70C}\gtrsim 1$.
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spelling doaj.art-de68c42ae33040ca9b003cc5c438a89c2023-03-09T12:34:47ZengCambridge University PressForum of Mathematics, Sigma2050-50942020-01-01810.1017/fms.2020.17THE FREE ENERGY OF THE TWO-DIMENSIONAL DILUTE BOSE GAS. I. LOWER BOUNDANDREAS DEUCHERT0https://orcid.org/0000-0003-3146-6746SIMON MAYER1ROBERT SEIRINGER2https://orcid.org/0000-0002-6781-0521Institute of Mathematics, University of Zurich, Winterthurerstrasse 190, 8057Zurich, Switzerland; Institute of Science and Technology Austria (IST Austria), Am Campus 1, 3400Klosterneuburg, Austria; ,Institute of Science and Technology Austria (IST Austria), Am Campus 1, 3400Klosterneuburg, Austria; ,Institute of Science and Technology Austria (IST Austria), Am Campus 1, 3400Klosterneuburg, Austria; ,We prove a lower bound for the free energy (per unit volume) of the two-dimensional Bose gas in the thermodynamic limit. We show that the free energy at density $\unicode[STIX]{x1D70C}$ and inverse temperature $\unicode[STIX]{x1D6FD}$ differs from the one of the noninteracting system by the correction term $4\unicode[STIX]{x1D70B}\unicode[STIX]{x1D70C}^{2}|\ln \,a^{2}\unicode[STIX]{x1D70C}|^{-1}(2-[1-\unicode[STIX]{x1D6FD}_{\text{c}}/\unicode[STIX]{x1D6FD}]_{+}^{2})$. Here, $a$ is the scattering length of the interaction potential, $[\cdot ]_{+}=\max \{0,\cdot \}$ and $\unicode[STIX]{x1D6FD}_{\text{c}}$ is the inverse Berezinskii–Kosterlitz–Thouless critical temperature for superfluidity. The result is valid in the dilute limit $a^{2}\unicode[STIX]{x1D70C}\ll 1$ and if $\unicode[STIX]{x1D6FD}\unicode[STIX]{x1D70C}\gtrsim 1$.https://www.cambridge.org/core/product/identifier/S2050509420000171/type/journal_article16W1016D50
spellingShingle ANDREAS DEUCHERT
SIMON MAYER
ROBERT SEIRINGER
THE FREE ENERGY OF THE TWO-DIMENSIONAL DILUTE BOSE GAS. I. LOWER BOUND
Forum of Mathematics, Sigma
16W10
16D50
title THE FREE ENERGY OF THE TWO-DIMENSIONAL DILUTE BOSE GAS. I. LOWER BOUND
title_full THE FREE ENERGY OF THE TWO-DIMENSIONAL DILUTE BOSE GAS. I. LOWER BOUND
title_fullStr THE FREE ENERGY OF THE TWO-DIMENSIONAL DILUTE BOSE GAS. I. LOWER BOUND
title_full_unstemmed THE FREE ENERGY OF THE TWO-DIMENSIONAL DILUTE BOSE GAS. I. LOWER BOUND
title_short THE FREE ENERGY OF THE TWO-DIMENSIONAL DILUTE BOSE GAS. I. LOWER BOUND
title_sort free energy of the two dimensional dilute bose gas i lower bound
topic 16W10
16D50
url https://www.cambridge.org/core/product/identifier/S2050509420000171/type/journal_article
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