Squashed Entanglement and Its Useful Properties
Squashed entanglement is an entanglement measure with useful properties such as additivity and monogamy. Its definition and applications.
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Quantum Information Theory
Entropy, channel capacity, teleportation, complexity classes and the theorems that define what quantum information can and cannot do.
155 articles
Irreversible Quantum Operations and Measurement
Measurements and noisy channels are irreversible quantum operations. How irreversibility arises and what it means for quantum computing.
Reversible Quantum Operations and Unitarity
Reversible quantum operations are unitary transformations. How reversible gates and circuits work and why unitarity matters in computing.
Phase Damping Channels and Coherence Decay
The phase damping channel models loss of coherence without energy loss. Its formalism, Markovian and non-Markovian dynamics and error correction.
Amplitude Damping Channels and Energy Loss
The amplitude damping channel models energy loss, such as a qubit decaying to its ground state. Its Kraus operators, effects and correction.
Quantum Depolarizing Channels: The Standard Noise
The depolarizing channel replaces a state with the maximally mixed state with some probability. Its representation, properties and uses as a noise model.
Entanglement Witnesses: Detecting Entanglement
Entanglement witnesses are observables that detect entanglement without full tomography. How they are built and used in experiments.
Quantum Symmetric States and Permutation Invariance
Symmetric states are unchanged when their particles are permuted. Their structure, entanglement properties and uses in computing and cryptography.
Strong Subadditivity: The Hardest Entropy Inequality
Strong subadditivity, proved by Lieb and Ruskai in 1973, is the key inequality of quantum entropy. Its statement, proof ideas and uses.
Quantum Subadditivity of Entropy, Explained
Subadditivity says the entropy of a whole is at most the sum of its parts. How it works for quantum systems and what entanglement changes.
The Quantum Asymptotic Equipartition Property
The quantum asymptotic equipartition property says that many copies of a state concentrate on a typical subspace. Why it underlies compression.
The No-Broadcasting Theorem for Mixed States
The no-broadcasting theorem extends no-cloning to mixed states: non-commuting states cannot be broadcast. Its statement, proof and uses.
