The effect of low temperatures on the sensitivity of radiometers

The behavior of radiometers at low temperatures, besides being of some interest to the theoretical physicist,(2) is of considerable importance to one desiring to carry radiant energy measurements to an extreme limit. Various workers have already pushed the sensitivity of such instruments as the thermocouple, radio micrometer, and radiometer into the region in which Brownian movement begins to mask observations so that any great gain in the sensitivity of existing instruments must come from some change in technique rather than from mere refinement of our instruments

Factorization of completely bounded bilinear operators and injectivity

We characterize injectivity of von Neumann algebras in terms of factoring bilinear maps as products of linear maps.Comment: 32 pages. See also http://www.math.tamu.edu/~roger.smith/ preprints.htm

Strong singularity for subalgebras of finite factors

In this paper we develop the theory of strongly singular subalgebras of von Neumann algebras, begun in earlier work. We mainly examine the situation of type \tto factors arising from countable discrete groups. We give simple criteria for strong singularity, and use them to construct strongly singular subalgebras. We particularly focus on groups which act on geometric objects, where the underlying geometry leads to strong singularity

The Solway Estuary: A socio-cultural evaluation of a coastal energy landscape

No abstract available

Strong singularity of singular masas in II₁ factors

A singular masa A in a II1 factor N is defined by the property that any unitary w ∈ N for which A=wAw* must lie in A. A strongly singular masa A is one that satisfies the inequality ||EA- EwAw*||∞,2 ≥||w- EA(w)||2 for all unitaries w ∈ N where EA is the conditional expectation of N onto A, and ||⋅||∞,2 is defined for bounded maps Φ : N → N by sup{||Φ (x)||2:x ∈ N,||x||≤1}. Strong singularity easily implies singularity, and the main result of this paper shows the reverse implication

Perturbations of C*-algebraic invariants

Kadison and Kastler introduced a metric on the set of all C*-algebras on a fixed Hilbert space. In this paper structural properties of C*-algebras which are close in this metric are examined. Our main result is that the property of having a positive answer to Kadison’s similarity problem transfers to close C*-algebras. In establishing this result we answer questions about closeness of commutants and tensor products when one algebra satisfies the similarity property. We also examine K-theory and traces of close C*-algebras, showing that sufficiently close algebras have isomorphic Elliott invariants when one algebra has the similarity property