# Non-Additivity in Classical-Quantum Wiretap Channels

@article{Tikku2020NonAdditivityIC, title={Non-Additivity in Classical-Quantum Wiretap Channels}, author={Arkin Tikku and Mario Berta and Joseph M. Renes}, journal={IEEE Journal on Selected Areas in Information Theory}, year={2020}, volume={1}, pages={526-535} }

Due to Csiszár and Körner, the private capacity of classical wiretap channels has a single-letter characterization in terms of the private information. For quantum wiretap channels, however, it is known that regularization of the private information is necessary to reach the capacity. Here, we study hybrid classical-quantum wiretap channels in order to resolve to what extent quantum effects are needed to witness non-additivity phenomena in quantum Shannon theory. For wiretap channels with…

## 2 Citations

### On contraction coefficients, partial orders and approximation of capacities for quantum channels

- Computer ScienceArXiv
- 2020

This work revisits the notion of contraction coefficients of quantum channels, which provide sharper and specialized versions of the data processing inequality and investigates the relation to other partial orders in the literature and their properties.

### Log-singularities for studying capacities of quantum channels.

- Computer Science
- 2020

A small linear increase from zero in some eigenvalue of a density operator makes the derivative of its von-Neumann entropy logarithmic, a $\log$-singularity, and methods for checking non-additivity and positivity of the coherent information of a noisy quantum channel are developed.

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