Upper Bound for the Grand Canonical Free Energy of the Bose Gas in the Gross–Pitaevskii Limit
Chiara Boccato, Andreas Deuchert, David Stocker
Abstract
We consider a homogeneous Bose gas in the Gross–Pitaevskii limit at temperatures that are comparable to the critical temperature for Bose–Einstein condensation in the ideal gas. Our main result is an upper bound for the grand canonical free energy in terms of two new contributions: (a) The free energy of the interacting condensate is given in terms of an effective theory describing its particle number fluctuations, and (b) the free energy of the thermally excited particles equals that of a temperature-dependent Bogoliubov Hamiltonian.
Topics & Concepts
MathematicsBose gasLimit (mathematics)Gross–Pitaevskii equationUpper and lower boundsEnergy (signal processing)Mathematical analysisMathematical physicsQuantum mechanicsBose–Einstein condensatePhysicsStatisticsCold Atom Physics and Bose-Einstein CondensatesQuantum, superfluid, helium dynamicsStrong Light-Matter Interactions