Hottest Questions This Month

5 votes

3 answers

1k views

How are IBM's 127 qubits more potent than the 5760 qubits D-Wave - Advantage_system6.1?

Shavarsh Shahoyan

5

modified May 15 at 13:29

8 votes

2 answers

2k views

Why doesn't Shor's algorithm output a solution for some numbers?

qiskit shors-algorithm period-finding-algorithm

CommunityBot

1

modified May 16 at 14:44

6 votes

1 answer

519 views

Can W gate be written only using H,T?

quantum-gate universal-gates transpile

DaftWullie

46.3k

answered yesterday

5 votes

1 answer

748 views

Is 60% accuracy high when calculating 1+1 on a quantum computer?

quantum-gate algorithm

Chan

51

modified May 5 at 11:35

2 votes

2 answers

526 views

Copying |0⟩, |1⟩ Qubits will break the no-cloning theorem?

no-cloning-theorem qubit-mapping

Tanner Swett

151

answered May 1 at 15:18

3 votes

4 answers

307 views

Cost of SWAP gate

quantum-circuit optimization

Danylo Y

5,433

modified May 15 at 11:09

2 votes

2 answers

354 views

Depth circuit optimization for 6-qubits GHZ state

entanglement circuit-construction

forky40

4,537

answered May 4 at 16:00

9 votes

1 answer

253 views

Is there a closure property for the entire Clifford hierarchy?

mathematics clifford-group clifford-hierarchy

Niel de Beaudrap

10.8k

modified May 20 at 13:33

2 votes

1 answer

219 views

Prove that sets of gates $\{CNOT^a, H^b, T^c\}$ are not universal

textbook-and-exercises universal-gates

glS♦

18.2k

modified May 1 at 19:04

8 votes

2 answers

195 views

A rigorous definition for an exponential quantum advantage

complexity-theory

shashvat

443

modified May 16 at 13:38

1 vote

2 answers

315 views

Can anybody explain the following circuit?

quantum-gate quantum-circuit universal-gates

DaftWullie

46.3k

answered Apr 26 at 6:44

1 vote

1 answer

108 views

Calculate $\sqrt[4]{X}$ for the Pauli $X$ gate

pauli-gates

glS♦

18.2k

modified May 1 at 19:37

4 votes

2 answers

167 views

What are the possible channels preserving purity of all input states?

quantum-operation

Danylo Y

5,433

modified May 13 at 10:47

3 votes

1 answer

159 views

Are the pure quantum states that make up a mixed state orthogonal?

quantum-state

DaftWullie

46.3k

modified May 20 at 6:59

0 votes

2 answers

70 views

Prove whether the state $|0\rangle\otimes|0\rangle+|1\rangle\otimes|+\rangle$ is entangled

entanglement textbook-and-exercises

glS♦

18.2k

modified Apr 30 at 19:31

2 votes

2 answers

135 views

Why can the CNOT representation $e^{i\frac{\pi}{4}\left(I-Z\right)\otimes\left(I-X\right)}$ hardly be found in books?

quantum-gate

manuel459

121

modified May 19 at 10:41

1 vote

1 answer

156 views

Why do we have only 3 Pauli gates X, Y and Z

pauli-gates

glS♦

18.2k

modified May 18 at 17:25

1 vote

1 answer

119 views

Does quantum superposition allow to apply an algorithm to all bits possibly in one shot?

superposition quantum-parallelism

glS♦

18.2k

modified May 3 at 10:06

2 votes

2 answers

84 views

Find a set of vectors on the Bloch sphere such that $\langle \psi_i | \psi_j \rangle = \frac{1}{\sqrt{n}}$

textbook-and-exercises bloch-sphere

Danylo Y

5,433

answered Apr 27 at 15:59

2 votes

2 answers

74 views

Why is $\Phi\otimes \operatorname{Id}_n$ being positive on maximally entangled states sufficient to know that $\Phi$ is CP?

quantum-operation

Norbert Schuch

4,998

modified May 8 at 23:53

2 votes

1 answer

136 views

Is there a quantum algorithm to find the xor of a dataset

algorithm

Yair Halberstadt

141

modified May 8 at 13:06

3 votes

2 answers

63 views

Understanding the output of a Deutsch-Jozsa circuit

algorithm ibm-q-experience deutsch-jozsa-algorithm

Sandipan Dey

160

modified May 8 at 15:19

3 votes

2 answers

80 views

Is a "Bell measurement" equivalent to a projective measurement in a different basis?

quantum-gate measurement bell-basis

glS♦

18.2k

modified May 21 at 9:11

3 votes

1 answer

78 views

Is the Pauli group isomorphic to the Heisenberg group over a finite field?

mathematics pauli-gates

Markus Heinrich

3,082

modified May 12 at 14:36

1 vote

1 answer

125 views

ket zero $|0\rangle = [1,\, 0]$, why a qubit which is initialized with zero is 1 in first basis state?

qiskit quantum-state

J.G.

103

modified May 10 at 23:27

3 votes

2 answers

66 views

qiskit qaoa.compute_minimum_eigenvalue

qiskit programming qaoa

ryanhill1

1,636

modified May 21 at 17:48

6 votes

1 answer

82 views

Why does code switching not allow for universal fault-tolerant quantum computation?

error-correction quantum-operation stabilizer-code

Darren B

21

modified May 5 at 8:31

2 votes

1 answer

62 views

Qiskit: How to implement a classical function?

qiskit quantum-gate circuit-construction

luciano

3,771

modified 2 days ago

0 votes

2 answers

48 views

How to sum equal terms in a superposition state?

quantum-state textbook-and-exercises

Rajiv Krishnakumar

804

answered May 17 at 14:57

1 vote

1 answer

79 views

What is the adjoint of the complementary channel?

quantum-operation kraus-representation

John Watrous

4,413

answered May 10 at 23:30

2 votes

1 answer

60 views

What makes dynamical decoupling a good method since the fidelity after using it can only reach 0.85 or so?

quantum-gate noise fidelity

Markus Heinrich

3,082

answered 10 hours ago

2 votes

1 answer

98 views

Applicability of the Bernstein-Vazirani to different modulus

algorithm bernstein-vazirani-algorithm

DaftWullie

46.3k

modified Apr 25 at 11:29

2 votes

1 answer

87 views

(Exercise-verification) Basic exercise on a 3 qubits circuit

textbook-and-exercises quantum-circuit

glS♦

18.2k

modified Apr 27 at 11:23

1 vote

2 answers

86 views

What's a circuit to compute the expectation value of an observable?

measurement

Cuhrazatee

440

modified May 5 at 23:02

4 votes

2 answers

51 views

Why should we purify a mixed state?

quantum-state

GaussStrife

1,083

answered May 20 at 13:46

0 votes

1 answer

83 views

Is there the number of CNOT restriction?

quantum-gate physical-realization

Chris E

186

answered May 12 at 3:54

1 vote

2 answers

50 views

Can one reset a qubit to the ground state on real IBM quantum processor?

qiskit programming

glS♦

18.2k

modified Apr 30 at 19:38

0 votes

1 answer

48 views

Qiskit gates out of order?

qiskit

Shashi Kumar

181

answered May 11 at 6:08

0 votes

1 answer

48 views

What is $j$ in the state $|\psi\rangle=\sqrt{(1-p)}|0\rangle + e^{j\phi}\sqrt{p}|1\rangle$?

ibm-q-experience

glS♦

18.2k

modified May 17 at 12:19

3 votes

1 answer

79 views

Is the Clifford group perfect (equals its own commutator subgroup)?

mathematics clifford-group

glS♦

18.2k

modified Apr 26 at 23:05

2 votes

2 answers

96 views

Qiskit compute mean expectation value

qiskit programming qaoa

Egretta.Thula

4,010

answered May 11 at 21:12

3 votes

1 answer

73 views

Qubit dephasing times

noise decoherence

Chris E

186

answered May 13 at 6:25

2 votes

1 answer

55 views

Construct a two-qubit quantum gate with given action using the gates ${CNOT, H, T}$

circuit-construction textbook-and-exercises quantum-circuit

glS♦

18.2k

modified May 1 at 19:03

3 votes

1 answer

54 views

What is the quantum strategy required to win the Magic Squares game

entanglement games contextuality peres-mermin-square

Condo

1,447

modified May 18 at 1:57

1 vote

1 answer

53 views

math behind rotation gate

quantum-gate mathematics matrix-representation

DaftWullie

46.3k

modified May 6 at 10:51

1 vote

1 answer

37 views

ket statevector of a 2-quibit system

qiskit quantum-state textbook-and-exercises

Mark S

6,777

modified May 17 at 23:12

0 votes

2 answers

76 views

Rxx gate as a set of rotations

quantum-gate quantum-state bloch-sphere physical-qubit

Zashibis

1

answered May 5 at 7:04

0 votes

2 answers

58 views

Create a 2-qubit quantum circuit with given state probabilities

quantum-gate quantum-state entanglement

Sandipan Dey

160

modified May 7 at 17:55

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