##### Reduced density matrix functional theory for bosons

Authors: C.L. Benavides-Riveros, J. Wolff, M.A.L. Marques, and C. Schilling

Ref.: Phys. Rev. Lett. 124, 180603 (2020)

Abstract: Based on a generalization of Hohenberg-Kohn’s theorem, we propose a ground state theory for bosonic quantum systems. Since it involves the one-particle reduced density matrix γ as a variable but still recovers quantum correlations in an exact way it is particularly well-suited for the accurate description of Bose-Einstein condensates. As a proof of principle we study the building block of optical lattices. The solution of the underlying v-representability problem is found and its peculiar form identifies the constrained search formalism as the ideal starting point for constructing accurate functional approximations: The exact functionals F[γ] for this N-boson Hubbard dimer and general Bogoliubov-approximated systems are determined. For Bose-Einstein condensates with NBEC≈N condensed bosons, the respective gradient forces are found to diverge, providing a comprehensive explanation for the absence of complete condensation in nature.

URL: arxiv.org

Bibtex:

@article{Benavides_Riveros_2020,
doi = {10.1103/physrevlett.124.180603},
url = {https://doi.org/10.1103%2Fphysrevlett.124.180603},
year = 2020,
month = {may},
publisher = {American Physical Society ({APS})},
volume = {124},
number = {18},
author = {Carlos L. Benavides-Riveros and Jakob Wolff and Miguel A.{\hspace{0.167em}}L. Marques and Christian Schilling},
title = {Reduced Density Matrix Functional Theory for Bosons},
journal = {Physical Review Letters}
}