Let $\mathcal{H}$ be a Hilbert space, and let $T: \mathcal{H} \rightarrow \mathcal{H}$ be a trace-class operator. Define $$ f_T(z) = \sum_{i=0}^\infty \mbox{Tr}(\wedge^k T) \cdot z^k, $$ the ordinary generating function for traces of exterior powers of $T$. Expressed another way, $$ f_T(z) = \mbox{Det}(I + zT) $$ where $\mbox{Det}$ is the Fredholm determinant. This function is entire, and can be considered a generalization of the characteristic polynomial. I am wondering if $$f_T(z) = e^z $$ for some natural choice of $T$ on some nice incarnation of Hilbert space. The motivation for this problem comes from representation theory, where finite minors of such a $T$ provide a formula for dimensions of irreps of $S_n$, the symmetric group on $n$ letters.