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Top Questions

5 votes
3 answers
1k views

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

8 votes
2 answers
2k views

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

6 votes
1 answer
519 views

Can W gate be written only using H,T?

5 votes
1 answer
748 views

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

2 votes
2 answers
526 views

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

3 votes
4 answers
307 views

Cost of SWAP gate

2 votes
2 answers
354 views

Depth circuit optimization for 6-qubits GHZ state

9 votes
1 answer
253 views

Is there a closure property for the entire Clifford hierarchy?

2 votes
1 answer
219 views

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

8 votes
2 answers
195 views

A rigorous definition for an exponential quantum advantage

1 vote
2 answers
315 views

Can anybody explain the following circuit?

1 vote
1 answer
108 views

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

4 votes
2 answers
167 views

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

3 votes
1 answer
159 views

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

0 votes
2 answers
70 views

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

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?

1 vote
1 answer
156 views

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

1 vote
1 answer
119 views

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

2 votes
2 answers
84 views

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

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?

2 votes
1 answer
136 views

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

3 votes
2 answers
63 views

Understanding the output of a Deutsch-Jozsa circuit

3 votes
2 answers
80 views

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

3 votes
1 answer
78 views

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

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?

3 votes
2 answers
66 views

qiskit qaoa.compute_minimum_eigenvalue

6 votes
1 answer
82 views

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

2 votes
1 answer
62 views

Qiskit: How to implement a classical function?

0 votes
2 answers
48 views

How to sum equal terms in a superposition state?

1 vote
1 answer
79 views

What is the adjoint of the complementary channel?

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?

2 votes
1 answer
98 views

Applicability of the Bernstein-Vazirani to different modulus

2 votes
1 answer
87 views

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

1 vote
2 answers
86 views

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

4 votes
2 answers
51 views

Why should we purify a mixed state?

0 votes
1 answer
83 views

Is there the number of CNOT restriction?

1 vote
2 answers
50 views

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

0 votes
1 answer
48 views

Qiskit gates out of order?

0 votes
1 answer
48 views

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

3 votes
1 answer
79 views

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

2 votes
2 answers
96 views

Qiskit compute mean expectation value

3 votes
1 answer
73 views

Qubit dephasing times

2 votes
1 answer
55 views

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

3 votes
1 answer
54 views

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

1 vote
1 answer
53 views

math behind rotation gate

1 vote
1 answer
37 views

ket statevector of a 2-quibit system

0 votes
2 answers
76 views

Rxx gate as a set of rotations

0 votes
2 answers
58 views

Create a 2-qubit quantum circuit with given state probabilities


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