Author: workhouse123
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What did Einstein think of quantum?
Einstein saw Quantum Theory as a means to describe Nature on an atomic level, but he doubted that it upheld “a useful basis for the whole of physics.” He thought that describing reality required firm predictions followed by direct observations.
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What is quantum simply?
Quantum Simply Cellular (QSC) microspheres are used in the quantitative analysis of cellular antigen expression. When stained with the same antibody that is used to label cells, they permit determination of the Antibody Binding Capacity (ABC) of the cells.
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What defines a quantum system?
The Quantum system is a composite system generated from different Quantum states. Such a system is manipulated through observation, collapsing the information in qubits. Another possibility is to control the Hamiltonian of the system.
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What is a simple example of quantum?
A quantum (plural: quanta) is the smallest discrete unit of a phenomenon. For example, a quantum of light is a photon, and a quantum of electricity is an electron. Quantum comes from Latin, meaning “an amount” or “how much?” If something is quantifiable, then it can be measured.
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What is the simplest quantum system?
Two-state systems are the simplest quantum systems that are of interest, since the dynamics of a one-state system is trivial (as there are no other states the system can exist in).
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Entanglement Measures
Owing to the importance of entanglement as a resource in quantum in- formation processing, it is necessary to construct measures of entanglement between two component systems. We saw in Chapter 4 a condition for the separability of 2-qubit states. For a generic higher dimensional density matrix to be separable, a test known as the positive…
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Fidelity
Another important measure for comparing probability distributions is the fidelity, which is easily extended to quantum states. This is variously defined in different texts, but we will stick to a simple operational definition here: F(p(x), q(x)) = X x p p(x)q(x). (11.50) The square root is used so that we have F(p(x), p(x)) = 1.…
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Distance Measures
An important consideration in information theory is the comparison of two systems: probability distributions in the classical context and states (pure or mixed) in the quantum. For such comparisons, various measures collectively labeled distance measures have been proposed. We’ll consider some of them here, to educate ourselves in the concepts involved. Characterization of Quantum Information…
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Entropy of composite systems
Some of the properties of the von Neumann entropy for composite systems are similar to those of Shannon entropy, while some others are quite different. We discuss a few here. 1. Concavity: S(ρ) is a concave function. That is, for a linear combination of states ρ = c 1 ρ A + c 2 ρ…
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Properties of the von Neumann entropy
Some properties of the von Neumann entropy immediately follow from the definition. Characterization of Quantum Information 225 1. The minimum value of S(ρ), zero, occurs for pure states. S(ρ) ≥ 0. (11.29) Thus even though a pure state embodies probabilities of measurement out- comes, the information carried by it is zero since it represents a…