Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physica A Statistical Mechanics and its Applications

Paramagnetic susceptibility and correlation functions of a d -dimensional classical Heisenberg ferromagnet via the two-time Green function method

L. S. Campana, A. Cavallo, L. De Cesare, Ugo Esposito, Adele Naddeo

Published Dec 27, 2016• 1 citation
Publisher
DOI
10.1016/j.physa.2016.12.026

Related papers

Construction of the correlation functions of the Heisenberg ferromagnet in the ferromagnetic and paramagnetic regions

Yu. A. Tserkovnikov

Theoretical and Mathematical Physics•Aug 1, 1979•7 citations

Correlation functions of a Heisenberg ferromagnet in the paramagnetic region

Yu. A. Tserkovnikov

Theoretical and Mathematical Physics•Jul 1, 1982•20 citations

Magnetic Properties of One-Dimensional Ferromagnetic Mixed-Spin Model within Tyablikov Decoupling Approximation

Yuan Chen, Xiang Ying, Chuang-Chuang Song

In this paper, we apply the two-time Green's function method, and provide a simple way to study the magnetic properties of one-dimensional spin-(S,s) Heisenberg ferromagnets. The magnetic susceptibility and correlation functions are obtained by using the Tyablikov decoupling approximation. Our results show that the magnetic susceptibility and correlation length are a monotonically decreasing function of temperature regardless of the mixed spins. It is found that in the case of S=s, our results of one-dimensional mixed-spin model is reduced to be those of the isotropic ferromagnetic Heisenberg chain in the whole temperature region. Our results for the susceptibility are in agreement with those obtained by other theoretical approaches.

Communications in Theoretical Physics•Oct 1, 2010•4 citations

Thermodynamics of low-dimensional spin- 12 Heisenberg ferromagnets in an external magnetic field within a Green function formalism

Tatiana N. Antsygina, M. I. Poltavskaya, Igor Poltavsky +1 more

The thermodynamics of low-dimensional spin-$\frac{1}{2}$ Heisenberg ferromagnets (HFMs) in an external magnetic field is investigated within a second-order two-time Green function formalism in the wide temperature and field ranges. A crucial point of the proposed scheme is a proper account of the analytical properties for the approximate transverse commutator Green function obtained as a result of the decoupling procedure. A good quantitative description of the correlation functions, magnetization, susceptibility, and heat capacity of the HFMs on a chain and square and triangular lattices is found for both infinite- and finite-sized systems. The dependences of the thermodynamic functions of two-dimensional HFMs on the cluster size are studied. The obtained results agree well with the corresponding data found by Bethe ansatz, exact diagonalization, high temperature series expansions, and quantum Monte Carlo simulations.

arXiv:0707.2899•Physical Review B•Jan 9, 2008•36 citations

Green’s function study of one-dimensional spin-1/2 Ising-Heisenberg ferromagnets

W. J. Zhang, J. L. Shen, Jian Xu +1 more

The one-dimensional spin-1/2 Ising-Heisenberg ferromagnets are studied by the Green's function method at finite temperatures. The Green's function is decoupled in terms of the correlation functions of 〈${\mathit{S}}_{0}^{\mathit{z}}$${\mathit{S}}_{\mathit{n}}^{\mathit{z}}$〉 and 〈${\mathit{S}}_{0}^{+}$${\mathit{S}}_{\mathit{n}}^{\mathrm{\ensuremath{-}}}$〉 under the constraint of 〈${\mathit{S}}^{\mathit{z}}$〉=0, from which a set of self-consistent equations are derived and solved numerically. The thermodynamic properties such as internal energy, specific heat, and zero-field parallel susceptibility are calculated. Our results predict the correct behavior for the correlation functions and thermodynamic quantities in the entire temperature region, in agreement both with the exact numerical results on the finite chain and the experimental data.

Physical review. B, Condensed matter•Feb 1, 1995•7 citations

Quantum inverse problem and green functions for the Heisenberg ferromagnet

P. P. Kulish, Fedor Aleksandrovich Smirnov

Physics Letters A•Jun 1, 1982•16 citations
In this paper, we apply the two-time Green's function method, and provide a simple way to study the magnetic properties of one-dimensional spin-(S,s) Heisenberg ferromagnets. The magnetic susceptibility and correlation functions are obtained by using the Tyablikov decoupling approximation. Our results show that the magnetic susceptibility and correlation length are a monotonically decreasing function of temperature regardless of the mixed spins. It is found that in the case of S=s, our results of one-dimensional mixed-spin model is reduced to be those of the isotropic ferromagnetic Heisenberg chain in the whole temperature region. Our results for the susceptibility are in agreement with those obtained by other theoretical approaches.
The thermodynamics of low-dimensional spin-12\frac{1}{2}21​ Heisenberg ferromagnets (HFMs) in an external magnetic field is investigated within a second-order two-time Green function formalism in the wide temperature and field ranges. A crucial point of the proposed scheme is a proper account of the analytical properties for the approximate transverse commutator Green function obtained as a result of the decoupling procedure. A good quantitative description of the correlation functions, magnetization, susceptibility, and heat capacity of the HFMs on a chain and square and triangular lattices is found for both infinite- and finite-sized systems. The dependences of the thermodynamic functions of two-dimensional HFMs on the cluster size are studied. The obtained results agree well with the corresponding data found by Bethe ansatz, exact diagonalization, high temperature series expansions, and quantum Monte Carlo simulations.
The one-dimensional spin-1/2 Ising-Heisenberg ferromagnets are studied by the Green's function method at finite temperatures. The Green's function is decoupled in terms of the correlation functions of 〈S0z{\mathit{S}}_{0}^{\mathit{z}}S0z​Snz{\mathit{S}}_{\mathit{n}}^{\mathit{z}}Snz​〉 and 〈S0+{\mathit{S}}_{0}^{+}S0+​${\mathit{S}}_{\mathit{n}}^{\mathrm{\ensuremath{-}}}$〉 under the constraint of 〈Sz{\mathit{S}}^{\mathit{z}}Sz〉=0, from which a set of self-consistent equations are derived and solved numerically. The thermodynamic properties such as internal energy, specific heat, and zero-field parallel susceptibility are calculated. Our results predict the correct behavior for the correlation functions and thermodynamic quantities in the entire temperature region, in agreement both with the exact numerical results on the finite chain and the experimental data.