Hottest Questions This Month

4 votes

2 answers

1k views

A necessary and sufficient condition for the existence of a nontrivial square root in Shor's algorithm

FDGod

1,376

modified Nov 16 at 22:50

4 votes

2 answers

2k views

How to properly understand Born's rule as written in the Feynman Lectures?

hft

848

modified Nov 17 at 16:25

9 votes

2 answers

479 views

Are these gate sets proven to be not universal?

Peter LeFanu Lumsdaine

103

modified Nov 16 at 13:43

4 votes

2 answers

325 views

How to convert a partially entangled state into maximally entangled using SLOCC

DaftWullie

55.7k

modified Nov 27 at 7:25

1 vote

1 answer

815 views

Why can't Grover's algorithm apparently solve this simple situation?

Mariia Mykhailova

8,785

answered Dec 4 at 1:22

2 votes

1 answer

197 views

Finding the eigenvalues of a qutrit state

Vladimir Lysikov

208

modified Nov 21 at 11:37

3 votes

2 answers

126 views

Equivalence of circuits in measurement-based QC

DaftWullie

55.7k

answered Nov 17 at 7:45

5 votes

2 answers

97 views

Decomposition of a $4 \times 4$ unitary matrix

DaftWullie

55.7k

answered Nov 29 at 7:58

4 votes

1 answer

200 views

How to characterize the extreme points of the set of CPTP maps?

Adam Zalcman

20.8k

modified Nov 24 at 13:48

4 votes

1 answer

123 views

Bug in stim HERALDED_PAULI_CHANNEL_1?

FDGod

1,376

modified Dec 1 at 9:22

3 votes

1 answer

119 views

Is possible to write a separable state as a finite or countable infinite sum of product states?

John Watrous

5,158

answered Nov 18 at 15:24

2 votes

1 answer

155 views

Problem with eigenvalue evaluation algorithm application on matrix $U$

Francescov20

35

modified Dec 1 at 10:19

2 votes

2 answers

119 views

Preparation of logical state with qLDPC code

Craig Gidney

33.4k

modified Nov 27 at 5:42

4 votes

1 answer

150 views

Questions on multi-controlled Toffolis and their implementation in Qiskit

mavzolej

1,872

modified 23 hours ago

5 votes

1 answer

107 views

Question about Nielson & Chuang Problem 9.2

Balint Pato

838

modified Nov 22 at 15:38

2 votes

1 answer

79 views

Classical capacity of quantum channel - Holevo quantity vs accessible information of a channel

glS♦

23.4k

modified Nov 18 at 19:18

2 votes

1 answer

124 views

Finding the "dual" basis of an overcomplete basis for Quantum State Tomography

glS♦

23.4k

modified Dec 3 at 16:06

1 vote

2 answers

95 views

Is there a way to perform Zero Noise Extrapolation with qiskit without using the runtime service?

Elijah Pelofske

677

answered Nov 29 at 20:40

3 votes

1 answer

90 views

What is the difference between quantum teleportation and quantum entanglement with dense coding?

Mark Spinelli

10.7k

modified Nov 14 at 13:47

1 vote

1 answer

70 views

Does quantum mutual information encompass information only about quantum correlations, or does it encompass both classical and quantum correlations?

banercat

755

modified Nov 17 at 12:31

1 vote

1 answer

114 views

Derivation of Choi-Jamiolkowski isomorphism

FDGod

1,376

modified Nov 14 at 16:43

2 votes

1 answer

114 views

study quantum hardware

FDGod

1,376

modified Nov 19 at 18:35

2 votes

1 answer

110 views

If_test() - Dynamic Circuits in qiskit

banercat

755

modified Nov 20 at 18:17

3 votes

1 answer

82 views

Why is the operator $M_a |x\rangle= |a \cdot x \pmod{N} \rangle $ unitary?

Mark Spinelli

10.7k

modified Nov 20 at 3:19

3 votes

1 answer

100 views

How much complexity is required to implement $\text{C$_\Pi$NOT}$ gate?

FDGod

1,376

modified Nov 29 at 6:38

2 votes

1 answer

94 views

+50

Number of logical cycles to implement $R_Z(\theta)$ gates in lattice surgery: why isn't it the number of layers $\times$ the $T$-count in $R_Z$?

Mariia Mykhailova

8,785

modified Dec 5 at 19:01

3 votes

1 answer

73 views

is a mixed states really a statistical mixture?

tpws

135

modified 5 hours ago

2 votes

1 answer

68 views

Quantum homomorphic encryption with a classical verifier - clarifying the setting?

Tristan Nemoz

5,354

answered Nov 29 at 20:29

2 votes

1 answer

67 views

Is a process matrix of rank $1$ unique?

glS♦

23.4k

modified Nov 27 at 10:55

1 vote

2 answers

51 views

Does the $\text{CNOT}$ gate activate if the control qubit is $-|1⟩?$

FDGod

1,376

modified Dec 6 at 21:24

1 vote

1 answer

104 views

How do I apply Amplitude Amplification for following state?

DaftWullie

55.7k

answered Nov 23 at 14:37

4 votes

1 answer

80 views

What is known about the size of the spectral gap of unital quantum channels?

glS♦

23.4k

modified Nov 18 at 19:21

3 votes

1 answer

79 views

What is the difference between classical-quantum and completely classical states?

glS♦

23.4k

modified Dec 3 at 16:08

1 vote

1 answer

61 views

How to convert stim encoder circuit to a parity check matrix?

tomek

25

modified Nov 23 at 23:28

2 votes

1 answer

60 views

What does "lift" mean in the Lifted Product (LP) Code?

Pavel Panteleev

46

answered Dec 4 at 5:56

3 votes

1 answer

94 views

Hadamard Gate on Cluster States

DaftWullie

55.7k

answered Nov 20 at 13:19

1 vote

1 answer

91 views

Problem with the mathematical definition of the eigenvalue algorithm on a specific exercise

Adam Zalcman

20.8k

modified Dec 1 at 16:49

3 votes

1 answer

54 views

Which single-qubit mixed states work for magic state distillation?

DaftWullie

55.7k

answered Nov 17 at 8:03

1 vote

2 answers

53 views

creating a generalised Bell state with gates

FDGod

1,376

modified Nov 17 at 18:34

1 vote

2 answers

68 views

Why $\sqrt{\rho} = P \sqrt{\rho}$ in the proof of quantum error correction conditions in Nielsen & Chuang?

Adam Zalcman

20.8k

modified Dec 1 at 14:48

2 votes

1 answer

65 views

Constructing a two 3-qubit state involving either X, Y or Z rotation gate

JoJo P

179

answered Nov 16 at 12:55

2 votes

2 answers

64 views

Conditioned gates with multiple classical bits

Egretta.Thula

9,132

answered Nov 20 at 15:50

2 votes

1 answer

64 views

How do I write a stim diagram to a file?

Craig Gidney

33.4k

answered Dec 1 at 6:36

2 votes

1 answer

82 views

How to measure in $\sigma_x$ basis in Qiskit? [duplicate]

Tristan Nemoz

5,354

modified Nov 16 at 9:22

1 vote

1 answer

80 views

How to properly generate circuit measurement results from detector error model

Martin Vesely

13.6k

modified Nov 17 at 18:14

2 votes

1 answer

77 views

How does this measurement in the Hadamard basis look like?

Mark Spinelli

10.7k

modified Nov 25 at 14:16

2 votes

0 answers

96 views

Mutual information of shared state is larger than expectation values

FDGod

1,376

modified Dec 1 at 9:25

0 votes

1 answer

57 views

Quantum Error Correction on a hexagonal lattice

Craig Gidney

33.4k

answered Dec 5 at 5:51

Top Questions

Looking for more? Browse the complete list of questions, or popular tags. Help us answer unanswered questions.