1998/06/05 by H. Kleinert, Hagen Kleinert, W. Kürzinger +2 · 2 citations
Mathematics · Physics and Astronomy · #Anharmonicity #Cold Atom Physics and Bose-Einstein Condensates #Coulomb #Hamiltonian (control theory) #Harmonic oscillator #Mathematical optimization #Mathematical physics #Mathematics #Perturbation (astronomy) #Perturbation theory (quantum mechanics) #Physics #Quantum #Quantum Mechanics and Non-Hermitian Physics #Quantum mechanics #Quantum, superfluid, helium dynamics #Quartic function #Singular perturbation #quant-ph
paper · pdf · doi:10.1088/0305-4470/31/41/005
published as J.Phys.A31:8307-8321,1998 · Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of paper also at http://www.physik.fu-berlin.de/~kleinert/kleiner_re267/preprint.html
arxiv created 1998/06/05 · openalex publication_date 1998/10/16 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In the variational approach to quantum statistics, a smearing formula efficiently describes the consequences of quantum fluctuations upon an interaction potential. The result is an effective classical potential from which the partition function can be obtained by a simple integral. In this work, the smearing formula is extended to higher orders in the variational perturbation theory. An application to the singular Coulomb potential exhibits the same fast convergence with increasing orders that has been observed in previous variational perturbation expansions of the anharmonic oscillator with quartic potential.