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3

It is a very interesting question. Quantum database would be a correlated collection of entangled ensembles of quantum data structures such as bloom filters, quantum graphs and quantum time series data distributed over quantum stream schema governed by Quantum Turing Machines and Quantum Fields as defined by David Deutsch, Richard Feymann, Yuri Mann among ...

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I believe Neilsen and Chuang were the first to use this particular notation. Previous work had referred to $S$ and $T$ as $\sigma_z^{1/2}$ and $\sigma_z^{1/4}$, respectively (Boykin et al. 1999). The use of $S$ may have been inspired by Deutsch's "S-matrix" (Deutsch 1989), though this was really a root-of-NOT gate. The use of $T$ may have been ...

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Quantum state: what a quantum system is in. It can be represented by a state vector, i.e., a normalized vector $|\psi\rangle \in \mathcal{H}^{2^n}$ where $n$ is the number of qubits in the system. (The state doesn’t need to be necessarily of a system composed of two-level quantum systems such as the qubit, it can be made up of quantum systems of any level; ...

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