37 How does bra-ket notation work? 2018-03-13T17:21:04.793

16 Quantum states are unit vectors... with respect to which norm? 2018-07-13T11:43:57.257

10 What do double wires mean in quantum circuits, and how do they relate to if statements? 2018-03-31T13:47:03.780

9 What does quantum error correction code notation stand for? 2018-04-16T21:26:17.250

8 What does it mean to "measure an operator"? 2020-12-09T01:20:52.837

6 How to compute the average value $\langle X_1 Z_2\rangle$ for a two-qubit system? 2018-04-10T18:24:33.557

6 Problem with the mathematical formulation of "qubitization" 2018-12-11T12:58:02.273

5 In Dirac notation, why do we have $\langle cf|g\rangle = c^*\langle f\vert g\rangle$? 2020-02-08T21:58:29.420

4 What do we mean by the notation $\lvert \mathbf{x}, 0\rangle$? 2018-04-26T09:23:24.410

4 What does it mean to express a gate in Dirac notation? 2019-04-27T19:08:13.363

4 Input and output qubit notation in quantum gates 2019-10-09T20:10:24.797

4 Difference between change of basis in bra-ket notation and matrix notation 2020-11-04T13:01:00.307

4 If the eigenvalues of $Z$ are $\pm1$, why are the computational basis states labeled with "$0$" and "$1$"? 2021-01-31T21:04:31.193

4 Are the two ways of interpreting the expression $(|a\rangle\otimes|b\rangle)(\langle c|\otimes\langle d|)(|e\rangle\otimes |f\rangle)$ equivalent? 2021-02-08T21:52:07.797

3 What does the notation $\lvert \underline{x} \rangle$ mean? 2018-04-26T12:10:43.443

3 Convention for expressing measurement in non-standard basis 2018-11-21T20:09:54.320

3 How to read Dirac notation (without algebra)? 2019-02-04T16:07:40.907

3 Notation for two qubit composite product state 2019-04-14T20:26:01.587

3 Writing the notation when gates act on non successive registers 2019-05-28T10:11:23.647

3 Notation question: How would one read $|0\rangle (|0\rangle+|0\rangle)$? 2019-09-29T22:11:43.573

3 Interpretation of specific Hamiltonian operator 2019-12-11T10:47:19.377

3 How should I understand the link between $x$ and $| x \rangle $? 2020-03-16T10:23:00.347

3 Confusing notation in Wikipedia's quantum channel article 2020-03-18T13:19:25.713

3 How to translate the Hadamard gate matrix into Dirac notation? 2020-10-04T19:35:47.530

3 What does $|j\rangle$ mean, when $j > 1$? 2020-12-06T13:10:31.213

3 Shouldn't the input state of Deutsh-Jozsa's algorithm look like $|0\rangle^{\otimes n}\otimes |1\rangle$ rather than $|0\rangle^{\otimes n}|1\rangle$? 2021-02-03T18:16:36.203

2 Notation for two entangled registers 2018-11-23T16:52:37.297

2 What is the notational convention for the single-qubit states $\lvert0\rangle\pm i\lvert1\rangle$? 2019-01-11T22:41:12.153

2 Is there a place online where I can catch up with all the notational syntax associated with quantum computing? 2019-02-10T00:55:58.463

2 What is the meaning of the state $|1\rangle-|1\rangle$? 2019-02-20T20:44:58.907

2 What is the meaning of writing a state in its Bloch representation? 2019-04-27T20:24:40.693

2 Writing the transformation matrix for the following in terms of Kronecker products of elementary 2-qubit gates 2019-04-29T07:16:55.513

2 Circuit construction and Dirac notation of the following operation 2019-05-21T18:05:50.460

2 What does the notation $\sigma_j^z$ mean for Pauli matrices? 2020-04-01T18:20:11.923

2 What does the notation $U(B,\beta) = \prod_{j =1}^n e^{-i \beta \sigma_j^x} $ mean in the context of QAOA? 2020-04-03T13:00:24.627

2 Is it wrong to say that $a$ and $b$ are the square roots of the detection probabilities in a qubit state $|\psi \rangle = a|0 \rangle +b|1 \rangle $? 2020-10-31T22:07:25.313

2 Is there a name for the terms that make up a state? 2020-12-07T16:13:09.857

2 What is the relation between observables (as defined in the measure-theoretic framework) and POVMs? 2021-01-21T19:36:32.903

1 A question about notation for quantum states 2018-12-05T06:45:19.087

1 Why is correlation in the $X$ basis represented as $X\otimes X = 1$? 2019-01-28T17:52:20.067

1 Qiskit gates in LaTeX representation: notation meaning 2019-02-20T15:00:41.783

1 How to write the map $\mathbb C\ni z\mapsto zv$ in bra-ket notation? 2019-02-26T13:57:24.847

1 Resources for quantum computing which do not use Dirac notation 2019-05-02T14:05:27.163

1 Which is the correct depiction of a qubit before it collapses? 2019-05-25T00:42:47.450

1 Kronecker notation of an operator 2019-05-27T17:32:32.543

1 Representing a Bell measurement on non adjacent qubits 2019-08-23T07:28:46.643

1 What does $\lvert \psi \rangle$ mean? 2019-11-17T11:33:53.273

1 What are $|+\rangle$ and $|-\rangle$? 2020-02-01T19:09:34.493

1 How does the graphical notation used to denote doubly-controlled gates work? 2020-07-14T09:46:19.500

1 How to represent the state vector form of a qubit in density matrix representation? 2020-10-30T07:05:28.450

1 What is the difference between the states $i|1\rangle$ and $|+i\rangle$? 2020-10-31T19:40:08.787

1 What are the physical meanings of the outer product when writing expressions for unitary gates? 2020-11-01T04:29:58.150

1 What does the notation $|\psi(0)\rangle = |0\rangle|n=0\rangle$ mean? 2020-11-05T15:53:17.053

0 What does "bipartite system" mean? 2021-02-19T12:11:17.473

0 What does "large-scale universal quantum computation" mean? 2021-02-21T14:30:23.630