Work

Existence of Kraus decomposition in infinite dimension via strongly-convergent direct process tomography

Year: 2026

Type: preprint

Abstract: An algorithm is presented for Kraus decomposition of a completely positive operator over separable (countably-infinite-dimensional) Hilbert spaces, together with an elementary proof that the generated sum convergences in strong-operator topology. This improves on the standard, nonconstructive, proof by fusing the abstract problem with practical process tomography. Kraus operators are generated one-by-one, each having one more guaranteed zero matrix entry than the previous one. In this way, the stream of outputs of the algorithm provides a coherent family of Kraus decompositions of restrictions of the target CP map to ever-larger subspaces.

Source: arXiv (Cornell University)

DOI: 10.48550/arxiv.2608.07207

Author: Lammert, Paul E.

Institution: Pennsylvania State University

Language: English

Topic: Quantum Information and Cryptography

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, Materials Research Science and Engineering Center, Harvard University, Division of Materials Research

Awards: G2515106960, G2893699457, G4742140246, G7683368480, MRSEC: Center for Nanoscale Science

OpenAlex ID: W7202142117

Cites: 15

Cited by: 1

Related to: 10