, Volume 3, Issue 1, pp 1–9 | Cite as

Irreversibility and quantum measurement—The observer’s role

  • Rajendra Bhandari
Foundations Of Physics


The role of the observer in physical theories in the sense of the observer’s viewpoint determining prominent features of the observed phenomena is discussed with reference to the problem of irreversibility and quantum measurement, the latter being closely related to the problem of classical behaviour of quantum systems. A completely subjective interpretation of irreversibility is proposed. It is claimed that irreversibility belongs only to phenomena as observed by a restricted observer who must project all phenomena on a restricted subset of the set of all possible states. The possibility of a completely unrestricted observer who does not see irreversibility is discussed.


Irreversibility entropy quantum measurement observer 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Brillouin L 1951J. Appl. Phys. 22 334–338; 1960Science and information theory, Second edition (Academic Press, New York) p. 164CrossRefADSMathSciNetGoogle Scholar
  2. Chew G F 1971Phys. Rev. D 4 2330CrossRefADSGoogle Scholar
  3. d’Espagnat B 1971Conceptual foundations of quantum mechanics (W. A. Benjamin Inc.)Google Scholar
  4. Merzbacher E 1961Quantum mechanics (John Wiley, New York) p. 25MATHGoogle Scholar
  5. Rosenfeld L 1972 inIrreversibility in the many-body problem ed J Biel and J Rae (Plenum Press, New York) p. 7Google Scholar
  6. Schrödinger E 1958Mind and matter (Cambridge University Press) p. 2Google Scholar
  7. Zeh H D 1971Foundations of quantum mechanics ed B d’Espagnat (Academic Press, New York) p. 263Google Scholar

Copyright information

© the Indian Academy of Sciences 1974

Authors and Affiliations

  • Rajendra Bhandari
    • 1
  1. 1.Raman Research InstituteBangalore

Personalised recommendations