User bilanush

7 votes

3 answers

4k views

Composing the CNOT gate as a tensor product of two level matrices

asked Feb 7, 2019 at 13:49

5 votes

1 answer

485 views

Decomposition of any 2-level matrix into single qubit and CNOT gates

asked Feb 8, 2019 at 12:39

5 votes

1 answer

2k views

What's a vector in the Bloch sphere representation?

asked Feb 28, 2019 at 3:34

5 votes

1 answer

1k views

The meaning of measurements in different bases

asked Mar 1, 2019 at 17:52

4 votes

2 answers

1k views

Why isn't the circuit performing a measurement in the Bell basis?

asked Mar 3, 2019 at 10:11

4 votes

1 answer

78 views

Are superdense coding and teleportation just a prototype or the 'only' type?

asked Mar 14, 2019 at 18:18

3 votes

1 answer

150 views

In error correction code why don't we imitate the Hamming code instead of the complicated Steane code?

asked Mar 10, 2019 at 21:21

3 votes

1 answer

112 views

How does the actual measurement collapsing an error to an orthogonal basis look like?

asked Mar 13, 2019 at 1:24

3 votes

2 answers

501 views

What does an observable in a different basis mean physically?

asked Mar 3, 2019 at 17:22

3 votes

1 answer

156 views

Do the probability amplitudes describe the probability of projective measurement?

asked Feb 11, 2019 at 12:37

3 votes

2 answers

493 views

What is the meaning of the state $|1\rangle-|1\rangle$?

asked Feb 20, 2019 at 20:44

2 votes

2 answers

425 views

The relationship between entanglement of vector states to matrix operations

asked Feb 24, 2019 at 21:26

2 votes

1 answer

141 views

What's the point of quantum gates being 'continuous'?

asked Feb 24, 2019 at 23:53

2 votes

2 answers

226 views

Why is measurement needed in teleportation?

asked Feb 28, 2019 at 2:26

2 votes

1 answer

72 views

Is there a place online where I can catch up with all the notational syntax associated with quantum computing?

asked Feb 10, 2019 at 0:55

2 votes

1 answer

216 views

Why is a density operator defined the way it's defined?

asked Mar 2, 2019 at 0:25

2 votes

2 answers

164 views

Why is it that the Pauli matrices and error correction operator act only on $|\psi\rangle\langle \psi|$ and not on state vector $|\psi\rangle$ itself?

asked Mar 6, 2019 at 17:13

2 votes

1 answer

174 views

Why does phase flip correction error? Why could any error be written as a linear combination of I, X, Z and ZX matrices?

asked Mar 9, 2019 at 2:03

2 votes

1 answer

184 views

How does Steane code use the classical Hamming code for error correction?

asked Mar 9, 2019 at 15:27

2 votes

1 answer

408 views

If CNOTs and single qubit gates are universal then why do we need to prove that controlled U operations can be composed by them as well?

asked Feb 17, 2019 at 16:10

1 vote

1 answer

146 views

What does it mean to perform a measurement in correspondence with different projections?

asked Mar 10, 2019 at 10:27

1 vote

1 answer

479 views

What does it mean that copying a state is impossible but creating a copy of by entangling is possible?

asked Mar 7, 2019 at 1:22

1 vote

1 answer

836 views

Clarification needed for the N&C proof that BQP ⊆ PSPACE

asked Mar 3, 2019 at 17:01

1 vote

3 answers

1k views

Is it correct to say that we need controlled gates because unitary matrices are reversible?

asked Feb 7, 2019 at 19:05

0 votes

1 answer

182 views

Why does $|P_U − P_V |$ equal $\langle \psi |U^{\dagger} M U|\psi\rangle −\langle \psi |V^{\dagger} M V |\psi\rangle$?

asked Feb 12, 2019 at 15:04

Stack Exchange Network

25 Questions

Composing the CNOT gate as a tensor product of two level matrices

Decomposition of any 2-level matrix into single qubit and CNOT gates

What's a vector in the Bloch sphere representation?

The meaning of measurements in different bases

Why isn't the circuit performing a measurement in the Bell basis?

Are superdense coding and teleportation just a prototype or the 'only' type?

In error correction code why don't we imitate the Hamming code instead of the complicated Steane code?

How does the actual measurement collapsing an error to an orthogonal basis look like?

What does an observable in a different basis mean physically?

Do the probability amplitudes describe the probability of projective measurement?

What is the meaning of the state $|1\rangle-|1\rangle$?

The relationship between entanglement of vector states to matrix operations

What's the point of quantum gates being 'continuous'?

Why is measurement needed in teleportation?

Is there a place online where I can catch up with all the notational syntax associated with quantum computing?

Why is a density operator defined the way it's defined?

Why is it that the Pauli matrices and error correction operator act only on $|\psi\rangle\langle \psi|$ and not on state vector $|\psi\rangle$ itself?

Why does phase flip correction error? Why could any error be written as a linear combination of I, X, Z and ZX matrices?

How does Steane code use the classical Hamming code for error correction?

If CNOTs and single qubit gates are universal then why do we need to prove that controlled U operations can be composed by them as well?

What does it mean to perform a measurement in correspondence with different projections?

What does it mean that copying a state is impossible but creating a copy of by entangling is possible?

Clarification needed for the N&C proof that BQP ⊆ PSPACE

Is it correct to say that we need controlled gates because unitary matrices are reversible?

Why does $|P_U − P_V |$ equal $\langle \psi |U^{\dagger} M U|\psi\rangle −\langle \psi |V^{\dagger} M V |\psi\rangle$?