Interaction-induced symmetry breaking in circular quantum dots
File(s)
Published version
Author(s)
Fadon, Andres Perez
Cassella, Gino
Sutterud, Halvard
Foulkes, WMC
Type
Journal Article
Abstract
This paper investigates interaction-induced symmetry breaking in circular quantum dots. We start by explaining what is known about symmetry breaking in quantum dots, pointing out that the anisotropic “static Wigner molecule” ground states frequently observed in simulations are created by interference effects that occur even in the non-interacting limit. They have nothing in common with the interaction-driven crystallization of the uniform electron gas described by Wigner. This leads us to define the term Wigner molecule more carefully via a finite analog of the spontaneous symmetry breaking that arises in the homogeneous electron gas when the interactions are strong. According to this definition, the charge density patterns characteristic of true interaction-induced Wigner molecules can only be seen if a small symmetry-breaking perturbation is applied to a strongly interacting quantum dot. A simple argument based on separation of variables into center-of-mass and internal coordinates shows that the strength of the perturbation required to produce a finite effect on the density tends to zero in the limit as the strength of the interaction tends to infinity. We confirm computationally that interaction-induced Wigner molecules satisfying this definition exist. The neural-network variational Monte Carlo method used in our simulations proves more accurate than the coupled cluster and diffusion Monte Carlo methods employed in previous benchmark calculations of quantum dots at small to intermediate interaction strengths. For high interaction strengths, our neural-network variational Monte Carlo energies agree very well with existing fixed-node diffusion Monte Carlo benchmarks, proving ∼0.01% better for small values of the total spin projection Sz but ∼0.01% worse for fully spin-polarized systems.
Date Issued
2025-04-14
Date Acceptance
2025-03-30
Citation
Journal of Chemical Physics, 2025, 162 (15)
ISSN
0021-9606
Publisher
American Institute of Physics
Journal / Book Title
Journal of Chemical Physics
Volume
162
Issue
15
Copyright Statement
© 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
http://arxiv.org/abs/2410.01652v1
Subjects
cond-mat.dis-nn
cond-mat.str-el
cond-mat.str-el
Publication Status
Published
Article Number
154305
Date Publish Online
2025-04-15