Acta Physica Academiae Scientiarum Hungaricae

, Volume 27, Issue 1–4, pp 111–129 | Cite as

On the theory of fermion density operators. I

The definition of the one-particle states and cluster expansions of the density operators
  • J. I. Horváth
  • I. K. Gyémánt


After the definitions of density operators (§2), the concept of single particle states is defined via the pure states of the first order reduced density operators (§3). Then the concepts of the NSO’s and NSG’s, as well as expansions in their terms are treated (§4). Furthermore,Kiang’s variational approach is discussed and improved (§5). Finally, cluster expansions of theN-particle density operators are obtained in terms of the first order reduced density operators in various cases.


Pure State Density Operator Single Particle State Cluster Expansion Reduce Density Operator 
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О теории операторов плотности фермионов I

Определение одночастичных состояний и кластерное разложение операторов плотности


После определения операторов плотности (§2) вырабатывается понятие простых частичных состояний на основе чистых состояний приведенных операторов плотности первого порядка (§3). Далее рассматривается понятие NSO и NSG и разложения по ним (§ 4). Дискутируется и развивается дальше вариационное приближение Кианга (5 §). Наконец в различных случаях даются кластерные разложения операторов плотностиN-частиц по приведенным операторам плотности первого порядка.


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Copyright information

© with the authors 1969

Authors and Affiliations

  • J. I. Horváth
    • 1
  • I. K. Gyémánt
    • 1
  1. 1.Department of Theoretical PhysicsJózsef Attila UniversitySzeged

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