Structure and positivity of linear maps preserving covariance under unitary evolution

Yuan Li, Shuaijie Wang, Xiaoming Xu

Let $\mathcal{H}$ be a complex finite-dimensional or infinite-dimensional separable Hilbert space, $\mathcal{B}(\mathcal{H})$ and $\mathcal{T}(\mathcal{H})$ be the Banach spaces of all bounded linear…