Entropy and asymptotics / Theorem
Sandwiched Renyi relative entropy data-processing inequality
Theorem statement
Let $\rho$ be a quantum state, $\sigma$ a positive semidefinite operator, and $\mathcal{N}$ a quantum channel. For $\frac{1}{2} \le \alpha < 1$ or $\alpha > 1$, the sandwiched Renyi relative entropy satisfies $\widetilde{D}_\alpha(\rho \| \sigma) \ge \widetilde{D}_\alpha(\mathcal{N}(\rho) \| \mathcal{N}(\sigma))$.
Sources
- Principles of Quantum Communication Theory: A Modern Approach
Sumeet Khatri, Mark M. Wilde, 2024
Lean context
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