# Tag Info

Accepted

### Has Nambu's notion of an "eigenoperator" found a place in the mathematical literature?

Such an $X$ is an eigenvector of $\,\operatorname{ad}(H)$. Joint eigenspace decompositions of several $\operatorname{ad}(H_i)$ are commonplace in math since the work of Lie, Killing, Cartan, with the ...
• 28.5k
Accepted

### Which elements live in the image of the canonical map $X \otimes_\mathcal{F} M \to B(M_*, X)$?

I follow the book of Effros+Ruan (which is a book, so not viewable online, but really is the nicest source I think). For any operator spaces $X,Y$ we can consider the operator space projective tensor ...
• 17.6k
Accepted

### Commutator ideal in nonunital C*-algebra

The answer is NO. Rordam and Robert MR3072284 have found a sequence $(A_n)_n$ of simple unital infinite dimensional C*-algebras such that $\prod A_n$ has a nonzero character. (Thanks are due to ...
• 8,951
Accepted

### Separable C* algebras and type I states

I don't think $\pi_\omega(A)''$ has that form. For example, take $A = M_2$ and let $\omega$ be the normalized trace. Then $\omega = \frac{1}{2}(\psi_1 + \psi_2)$ where \$\psi_i(x) = \langle xe_i, e_i\...
• 38.4k
Accepted

### "Open systems" version of Stone's Theorem for one-parameter groups of quantum operations

This has been generalized by Brian Davies to the general case, the article is Davies, E.B.: Quantum dynamical semigroups and the neutron diffusion equation. Rep. Math. Phys. 11(2), 169–188 (1977) A ...