A simplified approach to interacting Bose gases

Harvard University, Cambridge, Massachusetts, USA

April 1, 2020

I will discuss some new results about an effective theory introduced by Lieb in 1963 to approximate the ground state energy of interacting Bosons at low density. In this regime, it agrees with the predictions of Bogolyubov. At high densities, Hartree theory provides a good approximation. In this talk, I will show that the '63 effective theory is actually exact at both low and high densities, and numerically accurate to within a few percents in between, thus providing a new approach to the quantum many body problem that bridges the gap between low and high density.

Slides

PDF:

• Jauslin_Harvard_RM_2020.pdf

• tarball: 20harvard-rm-1.0.tar.gz
• git repository: 20harvard-rm-git (the git repository contains detailed information about the changes in the slides as well as the source code for all previous versions).

References

This presentation is based on

• [CJL19]: Analysis of a simple equation for the ground state energy of the Bose gas
  Eric Carlen, Ian Jauslin, Elliott H. Lieb, 2019
  (published in Pure and Applied Analysis, volume 2, issue 3, pages 659-684, 2020)
  pdf, source


• [CJLL20]: On the convolution inequality f>f*f
  Eric A. Carlen, Ian Jauslin, Elliott H. Lieb, Michael Loss, 2020
  (published in International Mathematics Research Notices, Volume 2021, Issue 24, pages 18604-18612, 2021)
  pdf, source