A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.

Quantum decoherence is the loss of quantum coherence. As long as there exists a definite phase relation between different states, the system is said to be coherent. This coherence is a fundamental pro…
71 questions
For questions about the meaning and usage of vocabulary specific to quantum computing or quantum information.
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For questions regarding (or related to) applications of quantum information theory in chemistry or applications of chemistry in quantum computing.
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Adiabatic quantum computation (AQC) is a form of quantum computing which relies on the adiabatic theorem to do calculations and is closely related to and may be regarded as a subclass of, quantum anne…
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For questions about QEM (Quantum Error Mitigation) which is different from Quantum Error Correction in that no extra qubits are used.
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Quantum assembly language (QASM) called OpenQASM is used to implement experiments with low depth quantum circuits. OpenQASM represents universal physical circuits over the CNOT plus SU(2) basis with s…
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For questions related to experiments with actual quantum computing devices and how to interpret their results. Also appropriate if the question can only be reasonable answered with an experiment (or e…
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For questions about quantum circuits having a small (polynomial) number of quantum gates; each gate is defined randomly. Random quantum circuits may be implementable shortly, and be used in noisy, in…
60 questions
In quantum mechanics, and especially quantum information and the study of open quantum systems, the trace distance T is a metric on the space of density matrices and gives a measure of the distinguish…
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For questions about the phenomena related to correlations among distant observers. For example, this tag should be used for questions about Bell or CHSH inequalities, or for questions about quantum st…
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It is the branch of physics and engineering concerned with the properties and transmission of photons. Use this tag for those questions about photonics which are relevant to quantum computing.
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Stabilizer states are quantum states that can be efficiently represented by some set of Pauli operators of which the state is a +1 eigenstate. Stabilizer states are used commonly in many areas of quan…
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For questions about the amplitude-amplitude algorithm. Do NOT use for general Grover's algorithm related question. Amplitude amplification is a technique in quantum computing which generalizes the ide…
56 questions
For questions about code which makes some use of QuTiP (Quantum Toolbox in Python). It is an open-source software library for simulating the dynamics of closed and open quantum systems. Please don't u…
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For questions asking about applications of quantum computers to solve practical problems.
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For questions related to positive-operator valued measures (POVMs), that is, sets of positive semi-definite operators summing to the identity matrix.
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PennyLane is a cross-platform Python library for quantum machine learning, automatic differentiation, and optimization of hybrid quantum-classical computations.
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A projection operator is one which when acts upon a quantum state (which is an element of a Hilbert space), "projects" it onto a subspace or onto another element of the same Hilbert space.
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For questions on theoretical models of quantum computations. Such models may be realistically 'build' in real machines, but not necessarily.
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For questions on Bell test experiments or Bell's inequality experiments, including but not limited to the CHSH and CH74.
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Having to do with continuous distributions, which are 'uniform' in the sense of being invariant under some relevant symmetry. In the case of quantum information theory, this usually relates to unitari…
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For questions mainly related to qudits, the unit of quantum information in d-level quantum systems.
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For questions about the specific realization of quantum computing that uses photons as qubits. Examples of gates include the Fabry-Perot cavity or linear optical components like beamsplitters. Questio…
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For questions related to quantum computing and quantum information research.
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For questions regarding the famous Simon's algorithm which solves Simon's problem exponentially faster than any deterministic or probabilistic classical algorithm, requiring exponentially less computa…
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A 54-qubit superconducting quantum processor by Google Quantum AI which is claimed to have been used to demonstrate quantum computational supremacy.
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For questions about classical-quantum (CQ) states and channels.
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The process of rewriting a given input circuit to match the topology of a specific quantum device, and/or to optimize the circuit for execution on present-day noisy quantum systems.
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In physics, the no-cloning theorem states that it is impossible to create an identical copy of an arbitrary unknown quantum state. (Wikipedia)
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Topological quantum computing is a theoretical quantum computing model that employs two-dimensional quasiparticles called anyons, whose world lines pass around one another to form braids in a three-di…
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For questions related to Noisy Intermediate Scale Quantum (NISQ) computing. NISQ computers cannot be classically simulated in a reasonable time but are not advanced enough to also be error corrected.
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Quantum walks are the quantum mechanical counterpart of classical random walks. This tag should be used for any question related to quantum walk models.
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Question about the Qiskit Runtime architecture that streamlines quantum computations. The service is designed to use classical compute resources to execute quantum circuits with more efficiency on qua…
34 questions
Graph-states are a class of quantum state that can be efficiently and uniquely represented by graphs. In the case of qubit graph states, each edge corresponds to a CZ operation applied between two qub…
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Continuous-variable quantum computing is a type of quantum computing that makes use of physical observables, like the strength of an electromagnetic field, whose numerical values belong to continuous …
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For questions related to quantum cryptography protocol BB84.
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