Summary
Explicit forms of Poincaré generators corresponding to lightlike irreducible unitary representations are discussed and connected. Using the Coester transformation, we obtain new forms of the generators in the lightlike countinuous-spin case showing a manifestly helicity character. These new forms and other well-known ones are related through unitary transformations (rotations in spin space) and are discussed in connection with the discrete-spin case.
Riassunto
Si discutono e collegano forme esplicite di generatori di Poincaré che corrispondono a rappresentazioni unitarie irriducibili alla luce. Per mezzo della transformazione di Coester, si ottengono nuove forme dei generatori nel caso di spin continuo simile alla luce, che mostrano un carattere manifestamente di elicità. Si mettono in relazione queste nuove forme ed altre ben note attraverso trasformazioni unitarie (rotazioni nello spazio di spin) e si discutono in rapporto con il caso a spin discreto.
Similar content being viewed by others
References
E. P. Wigner:Ann. Math.,40, 149 (1939).
G. J. Iverson andG. Mack:Ann. Phys.,64, 211 (1971).
G. J. Iverson andG. Mack:Phys. Rev. D,2, 2326 (1970).
J. S. Lomont andH. E. Moses:Journ. Math. Phys.,3, 405 (1962).
D. Korff:Journ. Math. Phys.,5, 869 (1964).
H. E. Moses:Journ. Math. Phys.,9, 2039 (1968).
A. Chakrabarti:Journ. Math. Phys.,12, 1813 (1971).
See also the set of references contained in the ref. (4,7).
L. L. Foldy:Phys. Rev.,102, 568 (1956).
Iu. M. Shirokov:Sov. Phys. JETP,6, 664, 919, 929 (1958).
F. Coester:Phys. Rev.,129, 2816 (1963).
J. Beckers andC. Pirotte:Nuovo Cimento,64 A, 439 (1969).
A. Chakrabarti:Journ. Math. Phys.,7, 949 (1966).
See also, in connection with helicity developments,J. Beckers:Journ. Math. Phys.,13, 915 (1971);J. Beckers andC. Pirotte:Ann. of Phys.,78, 258 (1973), and references therein.
G. Berlam andG. Eilam:Nucl. Phys.,25 B, 321 (1970).
The developments of this section have been extended to the discussion ofspacelike representations:J. Beckers andM. Jaspers: to be published in theProceedings of the V International Colloquium on Group-Theoretical Methods in Physics (New York, N. Y., 1976).
We refer the reader to sect.2 of ref. (7). and, for brevity, we only quote here Chakrabarti’s results of interest for our developments. Our notations are related to those of Chakrabarti byJ ≡M andM ≡ −N.
Author information
Authors and Affiliations
Additional information
To speed up publication, the author of this paper has agreed to not receive the proofs for correction.
Rights and permissions
About this article
Cite this article
Jaspers, M. On unitarity transformations and generators of lightlike poincaré representations. Nuov Cim A 35, 434–444 (1976). https://doi.org/10.1007/BF02731778
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF02731778