18 How to interpret a quantum circuit as a matrix? 2018-06-11T13:08:53.187

11 Advantage of simulating sparse Hamiltonians 2018-07-27T08:51:36.893

10 How to construct matrix of regular and "flipped" 2-qubit CNOT? 2019-01-11T08:33:10.977

9 Is there a name for the 3-qubit gate that does NOT NOT NOTHING? 2020-12-27T20:10:26.567

8 Could the Hadamard gate have been constructed differently with similar characteristics? 2019-10-13T01:15:06.540

8 Can arbitrary matrices be decomposed using the Pauli basis? 2019-11-09T12:43:20.377

8 How to check if a quantum circuit can be constructed for a given matrix representation? 2021-02-02T20:10:28.237

7 What are theta, phi and lambda in cu1(theta, ctl, tgt) and cu3(theta, phi, lam, ctl, tgt)? What are the rotation matrices being used? 2018-07-11T11:04:36.873

7 Matrix representation of continuous-variable gates 2018-07-12T21:15:06.683

7 $R_z$ gate representations 2018-10-11T23:50:19.760

6 What is the matrix of the iSwap gate? 2018-07-03T21:50:54.957

6 Solving linear systems represented by NxN matrices with N not power of 2 2018-07-27T09:09:01.500

6 Is there a tool that can give you the unitary representing a quantum circuit from just a string? 2018-08-04T11:46:11.020

6 How can we be sure that for every $A$, $A^\dagger A$ has a positive square root? 2018-12-02T11:28:41.900

6 Is quantum computer equivalent to Turing machine with matrix multiplication oracle? 2019-02-11T09:52:36.743

6 How to represent an $n$-qubit circuit in matrix form? 2020-03-05T12:54:28.547

5 Can we process infinite matrices with a quantum computer? 2018-08-17T15:32:26.547

5 Efficient implementation of the Clifford group for $n$ qubits 2019-01-10T09:47:36.523

5 Equivalent determinant condition for Peres-Horodecki criteria 2019-06-15T05:45:04.067

5 A basic question on circuits and matrix representation 2019-07-31T18:21:44.750

5 How to efficiently calculate the inverse of a Kronecker product? 2019-11-18T01:01:18.057

5 Representation of rotation operators $e^{-i\theta(I-Z_1\otimes Z_2 \otimes Z_3)}$ about arbitrary axis for $3$ qubits 2020-06-20T23:14:21.420

4 Projection operator on Time evolution Operator 2018-06-30T22:51:32.637

4 How to calculate tensor product for the magic square 2018-08-29T09:27:53.127

4 What is the matrix for the operator that implements a function to tell the parity of its argument? 2018-10-18T20:54:18.903

4 Simple proof that $(U \otimes V)(|x\rangle \otimes |y\rangle) = U|x\rangle \otimes V|y\rangle$? 2018-10-21T18:54:45.687

4 Differentiate between local and global unitaries 2019-03-01T07:03:38.450

4 What applications does the quantum gate [(i,1),(1,i)] have? 2019-05-19T20:57:21.017

4 How do I write the matrix for a CZ gate operating on nonadjacent qubits? 2019-12-12T17:21:20.710

4 Representing qubit swap using linear algebra 2019-12-24T16:47:13.257

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

4 What is the matrix for a SWAP operation on two qubits? 2020-12-13T18:49:59.063

4 Single-qubit rotations on a subspace within two-qubit unitary 2021-01-15T00:19:53.463

4 Is the column vector of a uniformly sampled random unitary matrix a uniformly sampled random state vector? 2021-01-18T23:00:36.327

3 Difference between 3 qubits, 2 qutrits & 1 six level qunit 2018-06-21T08:15:44.593

3 Nielsen & Chuang Exercise 2.2 - “Matrix representations: example” 2018-06-21T13:16:32.857

3 Nielsen & Chuang Exercise 2.3 - “Matrix representation for operator products” 2018-06-26T09:16:44.673

3 Clock matrix vs matrix clock 2018-12-17T23:44:23.927

3 Square root of CNOT and spectral decomposition of the Hadamard gate 2019-04-28T02:00:29.467

3 How to interpret the matrix representation of a quantum gate? 2019-04-30T18:02:05.173

3 Can I find the states of individual qubits in a quantum register using only linear algebra? 2019-09-16T21:36:32.740

3 What is the matrix representation for $n$-qubit gates? 2019-11-13T23:07:22.187

3 Non-unitary matrix decomposition as a sum of unitary matrices 2020-01-15T12:44:03.770

3 Show that a $CZ$ gate can be implemented using a $CNOT$ gate and Hadamard gates 2020-06-13T11:54:43.447

3 How to spot the matrix representation of the quantum NOT operation 2020-06-13T13:53:24.087

3 How are the Pauli $X$ and $Z$ matrices expressed in bra-ket notation? 2020-10-08T17:18:43.663

3 Creating a custom gate (given by a matrix) more efficiently 2020-10-26T21:27:43.907

3 How to find original matrix from eigenbasis and eigenvalues? 2020-11-11T13:11:48.007

3 D-WAVE QUBO Matrix Form 2020-12-07T09:17:21.390

3 XY Hamiltonian in a 1D Heisenberg Chain 2020-12-18T18:17:26.110

3 How do you represent one-quibit rotations in two registers as its own 4x4 unitary matrix? 2020-12-20T00:36:43.907

3 Mistake in using dirac notation when applying $X$ gate to vector 2020-12-21T18:11:00.050

2 Nielsen & Chuang Exercise 2.4 - “Matrix representation for identity” 2018-06-27T12:40:32.250

2 Matrix representation and CX gate 2018-10-24T08:59:54.197

2 Building a matrix corresponding to the teleportation circuit 2018-12-13T19:15:20.820

2 Nielsen & Chuang Exercise 2.2 - Matrix representations in different input and output basis 2019-02-07T12:36:00.657

2 Quantum addition and modulo operation using gates 2019-04-15T11:21:19.730

2 Matrix representation of multiple qubit gates (Hadamard transform on single wire) 2019-05-16T10:52:21.450

2 How do I write a tensor product of conditional gates in matrix form? 2019-06-11T21:50:52.787

2 Trace preserving condition in Choi's thorem 2019-07-31T22:29:34.057

2 Why is $Z_1Z_2$ spanned by this set ? Surely it's too small? 2019-08-14T17:19:47.417

2 How do I apply a controlled gate to specific qbits in the register? 2019-12-09T13:32:26.610

2 Syndrome extraction operator as matrix? 2019-12-27T09:25:11.560

2 2 qubit gate operation on multi qubit systems 2020-03-14T18:28:02.173

2 Matrix definition of the Ising XX gate 2020-04-14T12:54:50.970

2 Generic matrix exponential in Q# 2020-05-08T10:27:13.817

2 How does a $d\times\ell$ matrix of rank $\ell$ and with singular values all equal to 1 imply it is maximally entangled 2020-10-09T11:00:09.610

2 How to get subspace of quantum circuit? 2020-12-04T05:37:49.570

2 Qiskit PauliWeightedOperator in the matrix representation? 2020-12-29T21:10:25.133

2 Representation of multiple qubit matrices in Dirac notation 2021-01-22T08:51:02.060

1 Solving a circuit implementing a two-level unitary operation 2018-10-19T17:34:34.663

1 What's the matrix representation of this 3 qubit circuit? 2018-11-10T19:35:20.057

1 How to properly write the action of a quantum gate implementing an operator $U$ on the superposition of its eigenvectors? 2018-11-17T07:32:23.337

1 Error in showing $\operatorname{CPHASE}_{12}=\operatorname{CPHASE}_{21}$ in the matrix representation 2019-04-27T18:48:09.230

1 Controlled Z gate acting on 3 qubits in matrix form 2019-06-18T23:52:12.427

1 What is the general matrix for the Swap gate? 2020-02-19T21:16:41.160

1 Trying to use matrices for Hadamard and Controlled Not gates 2020-04-06T08:30:50.250

1 Show how the Bell state arises from the circuit with Hadamard and CNOT, using matrix notation 2020-04-12T08:21:57.407

1 Deriving a controlled Kraus operator from an uncontrolled Kraus operator 2020-05-26T23:14:11.827

1 Step-by-step passages in calculation 2020-07-06T22:44:41.747

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

1 How to make Toffoli gate using matrix form in multi qubits system? 2020-08-02T12:30:26.373

1 What is the matrix for measuring a superposition of general number of qubits in standard basis? 2020-08-05T06:07:21.483

1 Hadamard gate for three qubits; inconsistency between IBM and Matlab 2020-09-16T22:57:20.080

1 How do I apply a Hadamard gate on a given qubit, in matrix formalism? 2020-10-05T05:08:39.950

1 Get a sparse matrix of quantum circuit 2020-12-08T00:13:19.563

1 Is there a different way to represent Pauli gates in X basis? 2021-02-18T06:57:44.667

0 How are multi-qubit gates extended into larger registers? 2019-03-22T14:53:44.030

0 Controlled phase shift gate 2019-12-08T17:13:27.467

0 Find the decomposition of the following matrix into two level unitary matrices 2020-05-04T08:24:11.747

0 Nielsen & Chuang Exercise 4.34 "Measuring an operator" 2020-05-10T14:36:06.243

0 Expressing a term of an $n$-qubit Hamiltonian in terms of Pauli operators 2020-05-12T21:51:14.440

0 How to find the matrix representation of an operator from its action on a basis? 2020-06-26T15:52:04.527

0 How to implement quantum gate from matrix in Q# 2020-09-03T07:35:46.130

0 Information about two algorithms of Matrix product state 2020-09-28T06:59:01.107

0 How to force a matrix to be unitary given constraints on some of the elements? 2020-10-15T23:49:56.257

0 What is the effect of the reset gate on the matrix form of a gate/circuit? 2020-11-17T08:09:52.177

0 Quick question about Two-qubit SWAP gate from the Exchange interaction 2020-11-17T12:48:46.570

0 Compiling Quantum Circuits using the Palindrome Transform 2021-02-05T00:55:15.780