Crossref journal-article
AIP Publishing
Journal of Mathematical Physics (317)
Abstract

The following results are proved for a system of Ising spins σi = ±1 in zero magnetic field coupled by a purely ferromagnetic interaction of the form −Σi<j Jijσiσj with Jij ≥ 0, for arbitrary crystal lattice and range of interaction: (1) The binary correlation functions 〈σkσl〉 are always nonnegative (〈 〉 denotes a thermal average). (2) For arbitrary i, j, k, and l, 〈σiσjσk σl〉 ≥ 〈σiσj〉 〈σkσl〉. Consequences of these results, in particular the second, are: (i) 〈σkσl〉 never decreases if any Jij is increased. (ii) If an Ising model with ferromagnetic interactions exhibits a long-range order, this long-range order increases if additional ferromagnetic interactions are added. This last fact may be used to prove the existence of long-range order in a large class of two- and three-dimensional Ising lattices with purely ferromagnetic interactions of bounded or unbounded range.

Bibliography

Griffiths, R. B. (1967). Correlations in Ising Ferromagnets. I. Journal of Mathematical Physics, 8(3), 478–483.

Authors 1
  1. Robert B. Griffiths (first)
References 11 Referenced 386
  1. 10.1103/PhysRev.87.410 / Phys. Rev. (1952)
  2. {'key': '2024020715233457500_r2'}
  3. 10.1103/RevModPhys.36.856 / Rev. Mod. Phys. (1964)
  4. 10.1063/1.1705220 / J. Math. Phys. (1967)
  5. 10.1063/1.1704706 / J. Math. Phys. (1965)
  6. 10.1103/PhysRev.65.117 / Phys. Rev. (1944)
  7. 10.1073/pnas.55.4.676 / Proc. Natl. Acad. Sci. U.S. (1966)
  8. {'key': '2024020715233457500_r7'}
  9. 10.1017/S0305004100019174 / Proc. Cambridge Phil. Soc. (1936)
  10. 10.1103/PhysRev.136.A437 / Phys. Rev. (1964)
  11. {'key': '2024020715233457500_r10', 'first-page': '209', 'volume': '10', 'year': '1965', 'journal-title': 'Teoriya Veroyatnostei Primeneniya'} / Teoriya Veroyatnostei Primeneniya (1965)
Dates
Type When
Created 20 years, 7 months ago (Jan. 6, 2005, 3:06 p.m.)
Deposited 1 year, 6 months ago (Feb. 7, 2024, 4:49 p.m.)
Indexed 2 weeks, 3 days ago (Aug. 6, 2025, 9:01 a.m.)
Issued 58 years, 5 months ago (March 1, 1967)
Published 58 years, 5 months ago (March 1, 1967)
Published Print 58 years, 5 months ago (March 1, 1967)
Funders 0

None

@article{Griffiths_1967, title={Correlations in Ising Ferromagnets. I}, volume={8}, ISSN={1089-7658}, url={http://dx.doi.org/10.1063/1.1705219}, DOI={10.1063/1.1705219}, number={3}, journal={Journal of Mathematical Physics}, publisher={AIP Publishing}, author={Griffiths, Robert B.}, year={1967}, month=mar, pages={478–483} }