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arXiv · 2604.18600

Tomiyama-type maps with a diagonal perturbation

Anindita Bera·Bihalan Bhattacharya·Dariusz Chruściński
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Abstract

We investigate a two-parameter family of linear maps on matrix algebras, constructed as diagonal perturbations of classical Tomiyama maps. Employing the Choi matrix method alongside block-positivity techniques, we derive explicit necessary and sufficient conditions for positivity, complete positivity, and k-positivity across arbitrary dimensions. These conditions provide a transparent geometric characterization of the positivity regions within the parameter space.

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Anindita Bera, Bihalan Bhattacharya, Dariusz Chruściński. 2026-04-09. Tomiyama-type maps with a diagonal perturbation. https://arxiv.org/abs/2604.18600

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