Results · Quantum channels and memory

Factorizable rational quantum channels at an explicit distance from finite tracial baths

In plain wordsAn explicit twelve-qubit quantum channel with simple rational entries can be run by a maximally mixed environment of infinite size, yet stays an explicit positive distance, though a tiny one, from every channel that finite maximally mixed environments run or approach.

The result

As the paper states it, in briefExplicit rational channels that are factorizable but not limits of channels implementable with a finite maximally mixed environment, at a positive and explicit distance from that closure.

Questionson the index

How this was checked

Exact certificates
Standard-library checks of the payload, the constants and the certificates, listed in Section 8 of the paper.
Lean
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Novelty and credit

Novelty
Extends named prior work: version 1.0 of this work and Haagerup and Musat’s criterion for Schur channels; the characteristic-five certificate runs Wang and Zhi’s method. New, in the paper’s words: the compiler, the leakage theorem without letter singletons, and the root certificate.

Versionstwo, each with its own DOI

Every archived version, newest first. Dates are Zenodo publication dates. All versions: 10.5281/zenodo.23093838, which always resolves to the newest.
VersionDateDOINotes
2.0.010.5281/zenodo.23196593 PDF hosted here.
1.0.010.5281/zenodo.23093839Titled “A rational quantum channel beyond finite tracial baths”.

Paper, code and links

PDF

papers/rational-channels-v2.0.0.pdf, version 2.0.0, 554,621 bytes.

SHA-256 54decc274ca2b515e3c376aa42c47d68920b01b1d97ef323a189dd46ccb8b73c

Corrections

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Cite

@misc{mghirbi2026rationalchannels,
  author  = {Mghirbi, Nidhal and Douglas, Seth},
  title   = {Factorizable rational quantum channels at an explicit distance from finite tracial baths},
  year    = {2026},
  version = {2.0.0},
  doi     = {10.5281/zenodo.23196593},
  url     = {https://doi.org/10.5281/zenodo.23196593}
}

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