Physics:Quantum channel
A quantum channel is a Book I topic in the Quantum Collection. It is a mathematical description of a physical transformation of quantum states, usually represented as a completely positive trace-preserving map on density matrices. Quantum channels describe noise, measurement back-action, information loss, communication through a device, and the evolution of an open quantum system coupled to an environment. Important examples include unitary channels, depolarizing channels, amplitude-damping channels, phase-damping channels, and erasure channels. They provide the standard language for quantum information theory, quantum error correction, and realistic models of quantum computing hardware.
Overview
Placeholder: introduce quantum channels as completely positive trace-preserving maps that describe physical transformations of quantum states.
Key ideas
Placeholder: cover density matrices, open systems, completely positive maps, trace preservation, noise models.
Definition
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Physical meaning
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Examples of channels
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Role in open quantum systems
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See also
Table of contents (217 articles)
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Source attribution: Physics:Quantum channel
