Il Nuovo Cimento (1955-1965)

, Volume 2, Issue 4, pp 773–798 | Cite as

On the description of collective motion by th use of superfluous co-ordinates

  • H. J. Lipkin
  • A. de Shalit
  • I. Talmi
Article

Summary

By introducing superfluous co-ordinates a method is demonstrated for treating the problem of combined collective and individual particle aspects of nuclear structure. The application to the case of the center of mass gives a simple exposition of the method and rigorously defines conditions for the validity of the usual shell-model assumptions regarding the center of mass. The application to rotation gives results similar to those obtained by A. Bohr using a hydrodynamical model and by Inglis using a classical rotating shell model. The present treatment is rigorous except for the fundamental shell-model assumption, the replacement of the inter-particle potential by a single-particle potential which may not be spherically symmetric.

Riassunto

Si espone un metodo, basato sull’introduzione di coordinate superflue, atto a trattare il problema della struttura nucleare considerata contemporaneamente nei suoi aspetti a particelle singole o collettivo. L’applicazione al caso del centro di massa permette una esposizione semplice del metodo e definisce rigorosamente le condizioni per la validità delle ipotesi riguardanti il centro di massa prese a base del consueto modello a shell. L’applicazione al caso rotativo dà risultati simili a quelli ottenuti daA. Bohr servendosi di un modello idrodinamico e daInglis servendosi di un classico modello a shell. Il trattamento che presentiamo è rigoroso eccetto che per l’ipotesi fondamentale del modello a shell, la sostituzione al potenziale fra particelle di un potenziale monoparticellare che può non esser dotato di simmetria sferica.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. (1).
    A. Bohr andB. R. Mottelson:Dan. Mat. Fys. Medd.,27, no. 16 (1953).Google Scholar
  2. (2).
    A. Bohr:Rotational States of Atomic Nuclei (Copenhagen, 1954).Google Scholar
  3. (*).
    F. Villars: Private communication. Dr.Villars has independently treated the same problem discussed in this paper by essentially the same methods. The authors are indebted to Dr.Villars for sending them a copy of his manuscript and for several interesting comments.Google Scholar
  4. (4).
    The writers are indebted to Prof.G. Racah for directing their attention to these pathological cases.Google Scholar
  5. (5).
    E. Wigner:Gruppentheorie und ihre Anwendung auf die Quantenmechanik der Atomspektren (Braunschweig, 1931), p. 228.Google Scholar
  6. (6).
    Two terms are actually necessary for symmetry reasons, as has been pointed out byBohr andMottelson (see ref. (1)), but this distinction is not important here.Google Scholar
  7. (7).
    E. T. Whittaker:Analytical Dynamics (Cambridge, 1937), p. 10Google Scholar
  8. (8).
    H. B. G. Casimir:Rotation of a Rigid Body in Quantum Mechanics, Diss. (Groningen, 1931).Google Scholar
  9. (10).
    D. R. Inglis:Phys. Rev.,96, 1059 (1954).ADSCrossRefGoogle Scholar
  10. (11).
    H. B. G. Casimir: loc. cit. section V, 3.CrossRefGoogle Scholar
  11. (12).
    The use of other transformations has been investigated byA. Bohr: Private communication.Google Scholar
  12. (13).
    D. L. Hill andJ. A. Wheeler:Phys. Rev.,89, 1102 (1953).ADSCrossRefGoogle Scholar

Copyright information

© Società Italiana di Fisica 1955

Authors and Affiliations

  • H. J. Lipkin
    • 1
  • A. de Shalit
    • 1
  • I. Talmi
    • 1
  1. 1.Department of PhysicsThe Weizmann Institute of ScienceRehovothIsrael

Personalised recommendations