Quantum Wave Packet Dynamics and Spreading
A wave packet is a localized quantum state that spreads over time. Its evolution under the Schrödinger equation, tunneling, revivals and experiments.
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Tagged: Quantum Measurement
29 articles
Quantum Stochastic Processes and Their Calculus
Quantum stochastic processes describe quantum systems driven by noise. Their mathematics, Markovian and non-Markovian cases, and applications.
The Quantum Jensen-Shannon Divergence
The quantum Jensen-Shannon divergence is a symmetric, bounded measure of how different two quantum states are. Definition, properties and uses.
Entropic Uncertainty Relations, Explained
Entropic uncertainty relations express the uncertainty principle with entropies instead of standard deviations. Their forms, tests and uses.
Quantum Divergence Measures Between States
Divergences between quantum states, including relative entropy, fidelity, trace distance and Jensen-Shannon divergence, and where each is used.
Quantum Measurement Entropy and Information Gain
How measurement relates to entropy and information gain in quantum systems, and what uncertainty relations say about the trade-offs.
POVM: Measurement Beyond Projective Operators
Positive operator-valued measures describe the most general quantum measurements. Their definition, properties and uses beyond projective measurements.
Quantum Measurement Theory: What Collapse Means
Quantum measurement theory: observables, measurement operators, collapse, decoherence and the measurement problem, with the Zeno and eraser effects.
Quantum Information Inequalities and Strong Subadditivity
Key inequalities of quantum information: strong subadditivity, data processing, uncertainty relations, Bell inequalities and Tsirelson’s bound.
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 Fisher Information and Measurement Precision
Quantum Fisher information sets the best possible precision for estimating a parameter. Its definition, the Cramér-Rao bound and metrology uses.
Entanglement Entropy: Measuring Shared Information
Entanglement entropy measures how entangled one part of a system is with the rest. Definition, calculation and meaning in physics.
