Matrix Analysis
(Júlia Réffy, 2026)
- Finite-dimensional Hilbert spaces, Dirac formalism, bra and ket vectors. Trace and the Hilbert-Schmidt inner product.
- Special operators, spectral decomposition, functional calculus. Generators of B(H), self-adjoint subalgebras. Quantum states and measurements, Born rule.
- Absolute value, partial isometries, polar decomposition, singular values.
- Positive semi-definite order, minimum and maximum of self-adjoint operators. Trace minimum and maximum, optimal success and error probabilities of quantum state discrimination, max-relative entropy radius and center. Binary case, operational interpretation of the trace norm distance.
- Perspective function, classical f-divergences, convexity and monotonicity, variational distance, classical relative entropy and Rényi divergences.
- Monotonicity, convexity, and subadditivity of trace functions; Courant-Weyl-Fischer minimax theorem, Jensen inequality with operator weights. Neumann entropy, quantum Rényi entropies.
- Operator convex and operator monotone functions, basic examples, special integral representations.
- Tensor product of Hilbert spaces and operators. Asymptotic binary i.i.d. state discrimination problem, Audenaert’s inequality, attainability parts of the Stein, Chernoff and Hoeffding error exponents. Petz-type Rényi divergences, Umegaki relative entropy.
- Positive semi-definite block operators, Schur complement. Absolutely continuous part. Inequalities for positive and 2-positive super-operators.
- Operator perspective function, Kubo-Ando means, Petz-type and maximal quantum f-divergences, quantum Rényi divergences and relative entropies.
- Operator Jensen inequality, joint convexity/concavity of Kubo-Ando means and f-divergences.
- Discrete Weyl operators, partial trace via twirling. Completely positive maps in Kraus form, Stinespring dilation. Monotonicity of the Petz-type and the maximal f-divergences under CPTP maps.
- First and second derivatives of operator functions, characterization of operator monotonicity and convexity via derivatives.