Hottest Questions This Month

3

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2

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193

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How can I fill a unitary knowing only its first column?

modified Mar 22 at 4:16 DaftWullie 27.4k

4

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3

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173

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Quantum circuit to implement matrix exponential

quantum-gate qiskit hamiltonian-simulation hhl-algorithm

answered Mar 30 at 8:33 DaftWullie 27.4k

3

votes

3

answers

175

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What is the probability to get all qubits equal zero after QFT

quantum-state quantum-fourier-transform

answered Mar 30 at 8:37 DaftWullie 27.4k

5

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2

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310

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Why is Deutsch's gate universal?

circuit-construction nielsen-and-chuang universal-gates

modified Mar 18 at 13:35 DaftWullie 27.4k

3

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1

answer

159

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Does Controlled-U gate entangle qubits?

quantum-gate quantum-state quantum-information quantum-operation

answered yesterday DaftWullie 27.4k

2

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3

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320

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Why is Hilbert space considered especially large?

quantum-state nielsen-and-chuang

modified Mar 28 at 0:47 Jonathan Trousdale 1,551

3

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2

answers

129

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How should I understand the change of qubit's basis as a rotation?

quantum-state bloch-sphere unitarity hadamard

modified Mar 15 at 20:06 kludg 2,094

5

votes

1

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113

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CNOT gate in ZX-calculus

quantum-gate zx-calculus

modified Mar 19 at 22:32 Martin Vesely 3,613

2

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2

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176

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How to get the relative phase of a qubit?

measurement phase-estimation

answered Mar 31 at 10:23 Martin Vesely 3,613

1

vote

1

answer

139

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Simple algebraic explanation for normalizing states

quantum-gate entanglement hadamard

modified Mar 26 at 4:58 Mariia Mykhailova 4,718

3

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2

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38

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Is $R_x$, $R_y$, $R_z$, and $CNOT$ a Universal gate set?

universal-gates

answered Mar 30 at 7:35 DaftWullie 27.4k

6

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2

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64

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Information content of qubits

quantum-information bloch-sphere superdense-coding

modified Mar 14 at 6:48 kludg 2,094

1

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2

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49

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Entanglement - Natural and Unavoidable or Difficult to Do and Flimsy?

entanglement

answered Mar 30 at 7:56 DaftWullie 27.4k

2

votes

2

answers

78

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Is kronecker product identifiable?

mathematics tensor-product

modified Mar 11 at 17:40 Danylo Y 2,779

3

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2

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59

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How should I understand the link between $x$ and $| x \rangle $?

notation

answered Mar 16 at 12:58 Sam Jaques 608

2

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2

answers

96

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How to implement controlled gate based on measurement (quantum teleportation)?

ibm-q-experience measurement teleportation

answered Mar 16 at 14:13 luciano 21

3

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2

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67

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What is a local operator?

quantum-gate entanglement tensor-product

answered Mar 23 at 15:33 DaftWullie 27.4k

2

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1

answer

76

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What does the notation $U(B,\beta) = \prod_{j =1}^n e^{-i \beta \sigma_j^x} $ mean in the context of QAOA?

tensor-product notation qaoa

modified Apr 4 at 16:52 glS 9,264

2

votes

1

answer

42

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What does the notation $\sigma_j^z$ mean for Pauli matrices?

pauli-gates notation

modified Apr 2 at 12:48 glS 9,264

5

votes

2

answers

53

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What are some good resources for learning about photonic qubits?

resource-request physical-realization physical-qubit photonics optical-quantum-computing

answered Mar 24 at 5:45 SLesslyTall 1,316

3

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1

answer

83

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How does the teleportation circuit work after the initial entanglement?

quantum-state qiskit quantum-information teleportation

modified Mar 22 at 22:35 Martin Vesely 3,613

2

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2

answers

78

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Mitigating the noise in a quantum circuit

qiskit ibm-q-experience error-correction noise

modified Mar 13 at 18:46 Davit Khachatryan 910

1

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3

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88

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Error while running Quantum Teleportation Algorithm on real device using qiskit on IBM-Q

qiskit ibm-q-experience ibm

modified Mar 23 at 14:53 Frank 11

2

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1

answer

111

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Different QFT results when using Simulator or Quantum Machine

qiskit ibm-q-experience error-correction noise

modified Mar 19 at 8:44 JackOLantern 143

1

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2

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52

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Entanglement Swapping Circuit

ibm-q-experience simulation teleportation

answered Mar 31 at 6:09 HYW 197

4

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1

answer

66

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Represent a pure state in terms of 2 antipodal points on the Bloch sphere

quantum-state mathematics bloch-sphere

modified yesterday Davit Khachatryan 910

3

votes

1

answer

83

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How to decompose a multi-target controlled gate?

quantum-gate quantum-state machine-learning phase-estimation phase-kickback

modified Mar 14 at 11:59 Davit Khachatryan 910

2

votes

1

answer

64

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Problem with controlled rotation in HHL

hhl-algorithm

answered 2 days ago DaftWullie 27.4k

1

vote

1

answer

63

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Real backend for my students?

ibm-q-experience

answered Apr 2 at 0:54 Paul Nation 1,134

1

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2

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79

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Terminology : Are basis states the same as basis vectors?

terminology

answered Mar 23 at 20:36 Martin Vesely 3,613

1

vote

2

answers

78

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What is the risk factor on IBM's portfolio optimization notebook?

qiskit optimization vqe quantum-computing-for-finance

answered Mar 21 at 17:06 Martin Vesely 3,613

2

votes

2

answers

78

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How to prove that a matrix is an arbitrary unitary?

gate-synthesis unitarity

modified Mar 19 at 22:37 Martin Vesely 3,613

3

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1

answer

46

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$H = e^{i\pi/4} \sqrt{iNOT}$?

quantum-gate physical-realization hadamard

answered yesterday DaftWullie 27.4k

0

votes

1

answer

75

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Is Quantum Entanglement the one-dimensional spatial relationship between two particles as described by mathematics?

quantum-state entanglement

modified Mar 15 at 17:31 glS 9,264

3

votes

1

answer

58

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Confusing notation in Wikipedia's quantum channel article

quantum-channel notation

answered Mar 18 at 14:54 DaftWullie 27.4k

3

votes

1

answer

58

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Is there a systematic way to build quantum circuits?

algorithm quantum-information circuit-construction

modified Mar 24 at 11:00 Martin Vesely 3,613

1

vote

2

answers

51

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Problem with commutation of $e^{-iH_1t}$ and $e^{-iH_2t}$, where $H_1$ commutes with $H_2$

hamiltonian-simulation quirk

answered Apr 4 at 18:31 Davit Khachatryan 910

2

votes

1

answer

39

views

Gate corresponding to $-I$

quantum-gate quantum-state qiskit circuit-construction

modified Mar 31 at 17:58 Martin Vesely 3,613

1

vote

1

answer

63

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Trying to use matrices for Hadamard and Controlled Not gates

quantum-gate matrix-representation

modified 2 days ago Glorfindel 455

1

vote

2

answers

62

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May I deploy my C# code to Q# Azure quantum computing?

algorithm programming q#

modified Mar 25 at 3:29 Abhi 153

3

votes

2

answers

35

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How to implement exponentiation of a gate without breaking complexity?

circuit-construction complexity-theory quantum-fourier-transform phase-estimation

answered 2 days ago DaftWullie 27.4k

4

votes

1

answer

43

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What exactly does it mean to embed classical data into a quantum state?

algorithm quantum-state programming physical-qubit embedding

modified Mar 31 at 10:34 glS 9,264

1

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1

answer

54

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What does it mean to “measure a stabilizer”?

error-correction stabilizer-code

answered Mar 24 at 8:05 DaftWullie 27.4k

2

votes

1

answer

41

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Quantum circuit to get expectation values of Pauli matrices, given state $|\psi\rangle$

circuit-construction hhl-algorithm

answered Apr 1 at 9:14 DaftWullie 27.4k

1

vote

1

answer

41

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Does principle of deffered measurement imply information can travel faster than light?

circuit-construction teleportation

answered yesterday Mariia Mykhailova 4,718

2

votes

2

answers

66

views

Gate Y returns wrong phase in IBM's circuit composer

ibm-q-experience pauli-gates

answered Apr 2 at 22:34 Emil Prodan 56

1

vote

1

answer

49

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Like blockchains, other than the few quantum algorithms available out there, are quantum computers/algorithms a solution looking for a problem? [closed]

algorithm cryptography cryptocurrency

answered Mar 12 at 22:36 Johannes Jakob Meyer 316

-2

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0

answers

79

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As part of genomic epidemiology, using 2-Qubit Grover Search Algorithm to track and predict the target state of covid-19 mutation

grovers-algorithm simulation

modified Mar 14 at 11:54 Rúben André Barreiro 1

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