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  • QoS
    Quality of Service; an effort to provide different prioritization levels for different types of traffic over a network to deliver the right information to the right user in the right amount of time.
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  • Quantum Coherence
    When a physical system maintains a well defined phase relationship among its energy levels, enabling observation and utilization of quantum effects. Devices must be engineered carefully to exhibit this coherence. In typical systems, thermal and technical noise sources wash out quantum coherence (in a process known as decoherence). Quantum coherence is a necessary but not sufficient condition for quantum information applications.
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  • Quantum computer
    A processor which utilizes parallelism inherent in quantum superpositions to efficiently to perform specific algorithms. It can perform these with far fewer (in some cases exponentially fewer) resources than that possible with a traditional classical computer. The advantage of quantum computation is evident only in for large problems, but current state of the art demonstrations are limited to a small number (2-6) qubits and gates.
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  • Quantum cryptography
    A new technique for distributing cryptographic keys with extremely high levels of security, accomplished by a very clever twist on the fundamental laws of quantum physics.
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  • Qubit
    The analog of a bit register in a quantum computer. Unlike in a classical computer, a qubit can be in a superposition of 0 and 1 simultaneously, enabling massive parallelism in a quantum computer. Qubits must be constructed of physical systems which satisfy two important properties: (1) they possess two quantum levels which can be isolated and coherently manipulated; and (2) they can be coherently coupled to other qubits. Current candidates for qubits include superconducting Josephson Junction circuits, quantum dots, photons, neutral atoms, and ionic atoms.
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  • Query
    A user's (or agent's) request for information, generally as a formal request to a database or search engine.
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  • QuickTime
    A method of storing movie and audio files in a digital format.
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