The domain algebra of a CP semigroup

dc.creatorArveson, William
dc.date2000-05-24
dc.date.accessioned2026-07-25T22:47:01Z
dc.descriptionA CP semigroup is a semigroup of normal unit-preserving completely positive maps acting on the algebra B(H) of all operators on a separable Hilbert space H. Such a semigroup has a natural generator L; since the individual maps of the semigroup need not be multiplicative, the domain Dom(L) of L is typically an operator system, but not an algebra. However, we show that the set of all operators A in Dom(L), with the property that both A*A and AA* belong to Dom(L), is a *-algebra, called the domain algebra of the CP semigroup. Using this algebra, it is possible to draw a very close parallel with the Laplacian of a Riemannian manifold. We discuss properties of the "symbol" of L as the noncommutative counterpart of a (semidefinite) Riemannian metric, and give examples for which the domain algebra is, and is not, strongly dense in B(H).
dc.description19 pages typeset
dc.identifierhttps://arxiv.org/abs/math/0005251
dc.identifierhttp://arxiv.org/abs/math/0005251
dc.identifier.urihttps://dspace.dare.co.zw/handle/123456789/92459
dc.subjectOperator Algebras
dc.titleThe domain algebra of a CP semigroup
dc.typetext

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