Quantum Measurement Theory: What Collapse Means
Quantum measurement theory: observables, measurement operators, collapse, decoherence and the measurement problem, with the Zeno and eraser effects.
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Tagged: Quantum Information Theory
69 articles
The No-Cloning Theorem and Why It Holds
The no-cloning theorem, proved by Wootters, Zurek and Dieks in 1982, forbids copying an unknown quantum state. The proof and its consequences.
Quantum Channel Degradability and Capacity Formulas
Degradable channels have simple capacity formulas because the environment gets less than the receiver. Definitions, examples and uses.
Quantum Information Inequalities and Strong Subadditivity
Key inequalities of quantum information: strong subadditivity, data processing, uncertainty relations, Bell inequalities and Tsirelson’s bound.
Quantum Information Measures, Compared
The main quantum information measures compared: entropy, mutual information, relative entropy, entanglement and correlation measures.
Quantum Zero-Error Capacity and Perfect Transmission
Zero-error capacity asks how much information a channel can send with no errors at all. How quantum effects and entanglement change the answer.
Entanglement-Assisted Classical Capacity Explained
Entanglement-assisted classical capacity is the rate at which a channel carries classical bits when sender and receiver share entanglement.
Quantum Broadcast Channels and Their Capacities
Quantum broadcast channels send quantum information from one sender to several receivers. Architecture, capacities and applications.
Quantum State Merging and Negative Information
Quantum state merging transfers one party’s share of a state to another, and its cost can be negative, meaning entanglement is gained.
Quantum Hypothesis Testing: Deciding Between States
Quantum hypothesis testing decides between quantum states using measurements. Binary and multiple hypotheses, error exponents and the Chernoff bound.
Quantum Capacity Theorems and Their Proofs
The main quantum capacity theorems and how they are proved: coding theorems, entanglement-assisted capacity, additivity and superadditivity.
The Quantum Source Coding Theorem and Compression
Schumacher’s quantum source coding theorem shows quantum data can be compressed down to its von Neumann entropy. History, concepts and uses.
