Hostname: page-component-77c89778f8-9q27g Total loading time: 0 Render date: 2024-07-17T17:49:05.564Z Has data issue: false hasContentIssue false

Commutators of Operators on Hilbert Space

Published online by Cambridge University Press:  20 November 2018

Arlen Brown
Affiliation:
University of Michigan
Rights & Permissions [Opens in a new window]

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The purpose of this paper is to record some progress on the problem of determining which (bounded, linear) operators A on a separable Hilbert space H are commutators, in the sense that there exist bounded operators B and C on H satisfying A = BCCB. It is thus natural to consider this paper as a continuation of the sequence (2; 3; 5). In §2 we show that many infinite diagonal matrices (with scalar entries) are commutators and that every weighted unilateral and bilateral shift is a commutator.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1965

References

1. Dixmier, J., Les algèbres d﹜ opérateurs dans l'espace Hilbertien (Paris, 1957).Google Scholar
2. Halmos, P. R., Commutators of operators, Amer. J. Math., 74 (1952), 237240.Google Scholar
3. Halmos, P. R., Commutators of operators II, Amer. J. Math., 76 (1954), 191198.Google Scholar
4. Halmos, P. R., A glimpse into Hilbert space] Chap. I, Lectures on Mathematics (New York, 1963).Google Scholar
5. Pearcy, C., On commutators of operators on Hilbert space, Proc. Amer. Math. Soc, 16 (1965), 5359.Google Scholar
6. Wielandt, H., Über die Unbeschränktheit der Operatoren der Quantenmechanik, Math. Ann., 121 (1949), 21.Google Scholar
7. Wintner, A., The unboundedness of quantum-mechanical matrices, Phys. Rev., 71 (1947), 738739.Google Scholar