Hottest Questions This Month

9 votes

3 answers

1k views

Are quantum states like the W, Bell, GHZ, and Dicke state actually used in quantum computing research?

Frederik vom Ende

3,003

modified Aug 29 at 5:25

3 votes

2 answers

311 views

What is the Kronecker product of two 1D vectors?

user26872

109

answered Sep 9 at 19:32

4 votes

2 answers

149 views

Prove ${\rm tr}(\rho^2)={\rm tr}((\rho \otimes \rho')S)$ with $S$ the swap operator

Refik Mansuroglu

482

modified Sep 8 at 15:45

2 votes

4 answers

144 views

How to realize the index shift operation in quantum circuit?

Mark Spinelli

13.6k

modified Sep 8 at 14:58

3 votes

2 answers

252 views

Is it possible to approximately compile Toffoli using H and CSWAP?

Adam Zalcman

24.2k

modified Aug 25 at 11:04

1 vote

1 answer

317 views

Why are IBM's basis gates not linearly independent?

diemilio

1,356

modified Sep 4 at 19:33

4 votes

1 answer

192 views

Is the closest diagonal state to a given state always the dephased original state?

Frederik vom Ende

3,003

modified Sep 12 at 6:03

3 votes

1 answer

84 views

Density Matrices for states $|+\rangle$ and state represented by $\rho = \frac{|0\rangle \langle0| + |1\rangle \langle1|}{2}$

diemilio

1,356

modified yesterday

5 votes

2 answers

85 views

Finding a unitary transformation to swap the control bit

DaftWullie

60.8k

answered Sep 12 at 7:40

2 votes

1 answer

108 views

What are non-standard ways to describe the distance between states?

Rob

2,309

modified Sep 8 at 13:33

1 vote

1 answer

138 views

What is the operator-sum representation of the two-qubit depolarizing channel?

glS♦

26.4k

modified Aug 21 at 14:17

1 vote

1 answer

133 views

Is quantum computation effectiveness dependent on EPR non-locality?

CommunityBot

1

modified Sep 10 at 15:37

2 votes

1 answer

132 views

Clarification about a notation (or typo?) in ComplexityZoo for QAM class

Manish Kumar

831

modified Aug 26 at 7:37

1 vote

1 answer

160 views

What type of directions are fruitful to innovate in quantum hardware?

banercat

898

modified Aug 22 at 15:33

2 votes

1 answer

194 views

How to prepare a superposed state?

DaftWullie

60.8k

answered Sep 2 at 2:24

6 votes

1 answer

68 views

Why no $Z$'s in the $\operatorname{F} (\sum_{j=0}^{n-1} 2^j Z_j) \operatorname{F}^\dagger$ operator?

Craig Gidney

40.8k

answered Aug 27 at 21:11

2 votes

1 answer

137 views

Invalid coefficients in Quantum Process Tomography of the Hadamard gate

johhny

1

modified Aug 25 at 19:22

2 votes

1 answer

136 views

HHL eigenvalue inversion and further inverse QPE

Mark Spinelli

13.6k

modified 2 days ago

3 votes

1 answer

135 views

Why do Quantum Kernel Methods work when a large Hilbert space tends to make all samples orthogonal to each other?

forky40

7,448

answered Sep 6 at 18:31

4 votes

1 answer

130 views

Is a controlled Clifford gate in the third level of the Clifford hierarchy?

Ethan Davies

361

modified Aug 29 at 15:12

1 vote

1 answer

122 views

Power of Toffoli vs T in quantum logic

Craig Gidney

40.8k

answered Sep 8 at 22:42

1 vote

2 answers

129 views

converting a non-unitary matrix into quantum circuit

Egretta.Thula

11.6k

answered yesterday

2 votes

1 answer

91 views

Why does QPE still produce phase eigenvalues in HHL even though it operates on non-eigenvectors?

glS♦

26.4k

modified Sep 14 at 16:10

3 votes

1 answer

70 views

Finding a density matrix for a distirbution of pure states

MonteNero

3,181

modified Sep 12 at 15:34

2 votes

0 answers

180 views

+100

APPROX-QCIRCUIT-PROB: does it exist outside wikipedia? What is the correct formulation?

Doriano Brogioli

481

modified Sep 12 at 8:09

-1 votes

1 answer

107 views

Does this quantum circuit reproduce the oracle in Deutsch's algorithm?

glS♦

26.4k

modified Sep 4 at 7:53

3 votes

1 answer

61 views

Can you store $2(2^n -1)$ classical bits of information in $n$ qubits?

AG47

665

modified Sep 5 at 16:02

2 votes

2 answers

98 views

CX and CZ commutation

GaussStrife

1,105

modified 23 hours ago

1 vote

1 answer

93 views

How different quantum computing in four dimensions would be? [closed]

Matti Sarjala

124

modified Aug 27 at 9:02

1 vote

3 answers

91 views

Unsure about reduced state of entangled bits after measurement in different basis

Mark Spinelli

13.6k

modified Sep 1 at 22:51

1 vote

1 answer

82 views

Can we find the quantum state using the Bloch vector in the Bloch sphere?

Süleyman Emir Yılmaz

31

answered Sep 2 at 17:52

2 votes

1 answer

38 views

If $g \in S$, does this necessitate that $g^{\dagger} \in S$?

DaftWullie

60.8k

answered Sep 10 at 11:10

0 votes

1 answer

61 views

Modify a quantum state prepared with HHL [closed]

Mark Spinelli

13.6k

modified Sep 13 at 2:49

3 votes

1 answer

46 views

Showing that $V_{S} \subseteq \Pi_{S}$?

Rammus

6,261

answered Aug 20 at 11:15

3 votes

1 answer

95 views

Is distinguishing a certain outcome from an uncertain outcome BQP-hard?

Refik Mansuroglu

482

answered Sep 4 at 14:45

0 votes

2 answers

57 views

Is there a generalized quantum teleportation for n-qubit entangled states? [duplicate]

diemilio

1,356

modified Sep 6 at 1:12

-1 votes

1 answer

55 views

How to prepare a cluster state $\frac12(|0000\rangle+|0110\rangle+|1001\rangle-|1111\rangle)$ in Qiskit?

Adam Zalcman

24.2k

modified Sep 6 at 4:55

1 vote

1 answer

90 views

Why does quantum circuit need to be run even though the probability is already in the formula?

sheesymcdeezy

1,926

modified 2 days ago

2 votes

1 answer

68 views

How quantum laws hold on macroscopic level in classical computers?

Adam Zalcman

24.2k

modified Aug 20 at 13:48

1 vote

1 answer

67 views

What is the use of the given circuit identity?

Tal

113

modified Aug 20 at 10:41

0 votes

1 answer

86 views

Get Minimum Binary Value from Arbitrary Blackbox Oracle Result

taketoshi kinoshita

413

modified yesterday

3 votes

1 answer

66 views

Proof for how logical operators generated systematically will satisfy Pauli commutation

Yossarian

188

modified Sep 5 at 21:44

2 votes

1 answer

84 views

Is there any known characterization of k-Local Hamiltonian (k-LH) to distinguish if it has an efficient guiding state?

Norbert Schuch

7,683

modified Sep 4 at 15:28

2 votes

1 answer

65 views

When performing a projective measurement on a subsystem X entangled with another system Y, can the evolution of Y be unitary?

Rammus

6,261

modified Aug 29 at 17:56

1 vote

1 answer

83 views

Expectation Value of Observable from evolved statevectors using qiskit on Hardware

CuriousMind

33

modified Aug 30 at 8:36

2 votes

1 answer

80 views

What does a solvable Hamiltonian model mean?

Matti Sarjala

124

answered Sep 12 at 4:52

1 vote

1 answer

60 views

Independence of two systems

MonteNero

3,181

modified Sep 14 at 4:08

0 votes

1 answer

75 views

Can quantum computers eventually be programmed "normally"?

jecado

1,251

answered Aug 28 at 21:42

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