New paper: Conditional contraction coefficients and their applications to quantum networks arxiv.org/abs/2608.27171 Joint work with @christophhirche.bsky.social , Ian George, and Theshani Nuradha Motivating question: How much information does a noisy quantum channel destroy?

Conditional contraction coefficients and their applications to quantum networks

Contraction coefficients quantify the loss of distinguishability induced by a channel and provide a strong form of the data-processing inequality. While standard contraction coefficients ignore auxili...

arxiv.org

Accepted and published in Quantum: Quantum Doeblin Coefficients: Interpretations and Applications by Ian George, Christoph Hirche, Theshani Nuradha, and Mark M. Wilde doi.org/10.22331/q-2...

Quantum Doeblin Coefficients: Interpretations and Applications

Ian George, Christoph Hirche, Theshani Nuradha, and Mark M. Wilde, Quantum 10, 2115 (2026). In classical information theory, the Doeblin coefficient of a classical channel provides an efficiently computable...

quantum-journal.org

Information Contraction under $( varepsilon,δ)$-Differentially Private Mechanisms Theshani Nuradha, Ian George, Christoph Hirche http://arxiv.org/abs/2601.16845

Ian George, @christophhirche.bsky.social, Theshani Nuradha, & I have issued an update of our q. Doeblin coefficients paper: arxiv.org/abs/2503.22823 Main changes consist of an expanded section 8.5 on mixing, indistinguishability, & decoupling times of quantum Markov chains. See attached images

Cause for celebration: millions of euros in continued funding for research on photonics, measurements at the quantum frontier and personalised care for hearing loss. #LUH has been granted funding for three Clusters of Excellence and will apply for University of Excellence status.

Slides on "Quantum Doeblin Coefficients: Interpretations and Applications" available here: zenodo.org/records/1544... Joint work with Ian George, @christophhirche.bsky.social, and Theshani Nuradha

New preprint in preparation for ISIT: With Oxana Shaya, "Partial orders and contraction for BISO channels" scirate.com/arxiv/2504.1... Within the BISO channels the BEC and BSC are extremal in many aspects. We extend this to additional partial orders and show what role contraction plays here.

Partial orders and contraction for BISO channels

A fundamental question in information theory is to quantify the loss of information under a noisy channel. Partial orders and contraction coefficients are typical tools to that end, however, they are ...

scirate.com

Joint work w/ Ian George, Christoph Hirche @christophhirche.bsky.social, & Theshani Nuradha "Quantum Doeblin Coefficients: Interpretations and Applications": arxiv.org/abs/2503.22823 Great collaboration & enjoyable project! Interpretations of q. Doeblin coefficients in attached tables

Thanks for hosting me at Cornell last week, @markwilde.bsky.social !

Mark M. Wilde@markwilde.bsky.social · 2y ago

Great to have @christophhirche.bsky.social visiting us this past week! Attached photos show Christoph leaving quantum information divergence graffiti in the Cornell music studio before our jam session :) (next to the related graffiti I left some weeks ago)

The next Cornell ECE FIND seminar speaker on March 6 will be @christophhirche.bsky.social: find.engineering.cornell.edu/seminar/talk... "New quantum f-divergences and their applications" Looking forward to it!

New preprint: "Optimization Driven Quantum Circuit Reduction" w/ Bodo Rosenhahn & Tobias J. Osborne Transpiling quantum circuits well to specific gate sets is a hard but important problem near-term. We apply tools from ML to give an effective and scalable approach. scirate.com/arxiv/2502.1...

We're looking for a new addition to our group. Drop me a message if you're interested!

Quantiki@quantiki.bsky.social · 2y ago

The research group of Prof. Christoph Hirche @christophhirche.bsky.social at the University of Hannover (Germany) is looking for a motivated PhD student. #QuantumInformationTheory #QuantumComputing www.quantiki.org/position/phd...

Trying this out by announcing our new preprint: Not too long ago, @marcotomamichel.bsky.social and I gave a new definition of quantum f-divergences. Now, we teamed up with Salman Beigi to dive deeper into their properties and how they relate to previous definitions: scirate.com/arxiv/2501.0...

Some properties and applications of the new quantum $f$-divergences

Recently, a new definition for quantum $f$-divergences was introduced based on an integral representation. These divergences have shown remarkable properties, for example when investigating contractio...

scirate.com