Trace Functional eq i Sup f alpha
traceFunctional_eq_iSup_f_alpha
Plain-language statement
Step 1 (Variational formula): For α > 1, the trace functional equals the supremum of f_α over all PSD H: Q̃_α(ρ‖σ) = ⨆ (H : HermitianMat d ℂ) (_ : 0 ≤ H), f_alpha α H ρ σ. The optimizer is H_hat = σ^γ (σ^γ ρ σ^γ)^{α−1} σ^γ.
Source project: quantumInfo
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