Site occupation constraints in mean-field approaches of quantum spin systems at finite temperature

Abstract

We study the effect of site occupation on the description of quantum spin systems at finite temperature and mean-field level. We impose each lattice site to be occupied by a single electron. This is realized by means of a specific prescription. The outcome of the prescription is compared to the result obtained by means of a projection procedure which fixes the site occupation to one particle per site on an average. The comparison is performed for different representations of the Hamiltonian in Fock space leading to different types of mean-field solutions. The behaviour of order parameters is analyzed for each choice of the mean-field and constraint which fixes the occupation rate at each site. Sizable quantitative differences between the outcomes obtained with the two different constraints are observed.

arXiv comment18 pages, 2 figures

References in corpus (6)

• Quantum Orders and Symmetric Spin Liquids
• Exact spectra, spin susceptibilities and order parameter of the quantum Heisenberg antiferromagnet on the triangular lattice
• Algebraic spin liquid as the mother of many competing orders
• Many-body spin Berry phases emerging from the $\pi$-flux state: antiferromagnetic/valence-bond-solid competition
• Generalized Elitzur's Theorem and Dimensional Reduction
• Semi-fermionic representation of SU(N) Hamiltonians

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• Strict site-occupation constraint in 2d Heisenberg models and dynamical mass generation in $QE{D}_3$ at finite temperature
• Chiral symmetry restoration in (2+1)-dimensional $QED$ with a Maxwell-Chern-Simons term at finite temperature
• Magnetic properties of antiferromagnetic quantum Heisenberg spin systems with a strict single particle site occupation
• Interacting potential between spinons in the compact QED3 description of the Heisenberg model
• Effects of a strict site-occupation constraint in the description of quantum spin systems at finite temperature