English

Block quantum dynamical semigroups of completely positive definite kernels

Operator Algebras 2025-01-17 v2

Abstract

Kolmogorov decomposition for a given completely positive definite kernel is a generalization of Paschke's GNS construction for the completely positive map. Using Kolmogorov decomposition, to every quantum dynamical semigroup (QDS) for completely positive definite kernels over a set SS on given CC^*-algebra A,\mathcal{A}, we shall assign an inclusion system F=(Fs)s0F = (F_s)_{s\ge 0} of Hilbert bimodules over A\mathcal{A} with a generating unit ξσ=(ξsσ)s0.\xi^{\sigma}=(\xi^{\sigma}_s)_{s\ge 0}. Consider a von Neumann algebra B\mathcal{B}, and let T=(Ts)s0\mathfrak{T}=(\mathfrak{T}_s)_{s\ge 0} be a QDS over a set SS on the algebra M2(B)M_2(\mathcal{B}) with Ts=(Ks,1LsLsKs,2)\mathfrak{T}_s=\begin{pmatrix}\mathfrak{K}_{s,1} & \mathfrak{L}_s\\\mathfrak{L}_s^*& \mathfrak{K}_{s,2} \end{pmatrix} which acts block-wise. Further, suppose that (Fsi)s0(F^i_s )_{s\ge 0} is the inclusion system affiliated to the diagonal QDS (Ks,i)s0(\mathfrak{K}_{s,i})_{s\ge 0} along with the generating unit (ξs,iσ)s0,(\xi^{\sigma}_{s,i} )_{s\ge 0}, σS,i{1,2}\sigma\in S,i\in \{1,2\}, then we prove that there exists a unique contractive (weak) morphism V=(Vs)s0:Fs2Fs1V = (V_s)_{s\ge 0}:F^2_s \to F^1_s such that Lsσ,σ(b)=ξs,1σ,Vsbξs,2σ\mathfrak{L}_s^{\sigma,\sigma'}(b)=\langle \xi_{s,1}^{\sigma},V_s b\xi_{s,2}^{\sigma'}\rangle for every σ,σS\sigma',\sigma\in S and bB.b\in \mathcal{B}. We also study the semigroup version of a factorization theorem for K\mathfrak{K}-families.

Keywords

Cite

@article{arxiv.2401.16846,
  title  = {Block quantum dynamical semigroups of completely positive definite kernels},
  author = {Santanu Dey and Dimple Saini and Harsh Trivedi},
  journal= {arXiv preprint arXiv:2401.16846},
  year   = {2025}
}
R2 v1 2026-06-28T14:31:27.838Z