Infinite-order cumulant expansion for spins

Michele Parrinello and Tadashi Arai
Phys. Rev. B 10, 265 – Published 1 July 1974
PDFExport Citation

Abstract

The cumulant expansion for spins developed previously is rearranged and extended up to an infinite order in perturbation. A pair of spin-deviation lines is considered as a propagator and, as an additional propagator appears and interacts with the original one, that part of the diagram is defined as a self-energy correction. All cumulant corrections are decomposed and added to the corresponding self-energy corrections, so that self-energy corrections and their cumulant corrections are automatically calculated together exactly. The contribution of a self-energy correction to a diagram depends on the geometry of the incoming and outgoing spin-deviation lines of the self-energy diagram, yielding a new type of perturbation expansion. Numerical results suggest that the nature of the spin-spin correlation in the spin-1/2 case is distinct from that in other cases and that spins behave like fermions rather than bosons in this limit.

  • Received 7 February 1974

DOI:https://doi.org/10.1103/PhysRevB.10.265

©1974 American Physical Society

Authors & Affiliations

Michele Parrinello

  • Istituto di Fisica, Università di Messina, Messina, Italy
  • Gruppo Nazionale di Struttura della Materia del Consiglio, Nazionale delle Ricerche, Messina, Italy

Tadashi Arai

  • Argonne National Laboratory, Argonne, Illinois 60439

References (Subscription Required)

Click to Expand
Issue

Vol. 10, Iss. 1 — 1 July 1974

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×