Top Questions

8 votes
3 answers
248 views

In Schur-Weyl's duality, why is the commutant of $\pi_k(S_k)$ spanned by $U(d)^{\otimes k}$ matrices?

6 votes
3 answers
394 views

Can a CPTP map increase the purity of a state?

5 votes
4 answers
102 views

$U_1\oplus U_2$ decomposable into $I\oplus U$ and 1-qubit gates?

4 votes
4 answers
138 views

How do I transform a $ZZ$ interaction unitary into a $\text{CZ}$ gate?

7 votes
2 answers
296 views

How can quantum error correction correct small rotations/continuous errors?

5 votes
1 answer
304 views

What exactly is a subsystem code?

3 votes
2 answers
237 views

Is it always possible to write the state corresponding to a set of stabilizer generators?

3 votes
2 answers
290 views

Python package for quantum computations based on symbolic variables

3 votes
2 answers
131 views

What can we say about the eigendecomposition of quantum channels?

3 votes
2 answers
87 views

Are measurements in $X$ and $Z$ bases being equal enough to prove equality of quantum states?

2 votes
2 answers
248 views

TranspilerError: 'Number of qubits (40) in QAOA is greater than maximum (30) in the coupling_map'

3 votes
1 answer
150 views

Why is the coefficient-squared the probability, and not just the coefficient itself?

3 votes
1 answer
247 views

How to simulate low-rank hamiltonian?

1 vote
2 answers
246 views

What goes above this code fragment?

4 votes
1 answer
267 views

Clifford group without the phase gate

3 votes
1 answer
328 views

Why do the same circult yields very different results from different IBM backends?

4 votes
2 answers
117 views

Compute the exact minimum distance of a QECC with integer linear programming method

2 votes
3 answers
129 views

Is $|A\rangle = \frac{1}{\sqrt2} |00\rangle + \frac{1}{\sqrt2} |01\rangle$ a valid quantum state?

2 votes
3 answers
127 views

Are GHZ states absolutely maximally entangled?

2 votes
1 answer
193 views

What information about the logical state does one obtain from the stabilizers?

4 votes
1 answer
192 views

How do magic states circumvent the Eastin-Knill theorem?

4 votes
1 answer
145 views

Requirement of vector 'b' in the definition of Phase Estimation Sampling (PES)

1 vote
3 answers
175 views

Equivalence of quantum circuits

3 votes
2 answers
87 views

Time Complexity of Deustch Algorithm

1 vote
1 answer
175 views

Quantum Circuit evaluation Qiskit vs. AWS Braket SDK

2 votes
2 answers
98 views

Resources for understanding non-unitary channels and operators

4 votes
1 answer
158 views

Is it possible to implement the controlled-S gate, such that the inner gate between the CNOTs belongs to the Clifford?

7 votes
2 answers
74 views

What is the definition of physical gate error rate?

4 votes
2 answers
69 views

What's the trace distance between $|0\rangle^{\otimes n}$ and $\frac{1}{\sqrt{2}}\big(|0\rangle^{\otimes n} + |1 \rangle^{\otimes n} \big)$?

4 votes
1 answer
112 views

Can you decompose a 4-qubit Toffoli gate (CCCX) into basic gates without an ancillary state?

3 votes
2 answers
237 views

Prove that there is no polynomial size quantum algorithm for a Simon's problem with no promise on the input

3 votes
2 answers
83 views

In what sense does quantum tomography "determine the state prior to the measurements"?

3 votes
1 answer
118 views

For stabilizer codes, is a certain logical operation unique?

4 votes
2 answers
90 views

Show that all extensions of $\rho$ can be obtained as a channel applied to its purification

0 votes
1 answer
87 views

Are there logical operations unique to topological quantum computing?

0 votes
1 answer
87 views

What is the oracle in every quantum algorithm?

6 votes
1 answer
86 views

How to get smaller stabilizer codes with Gottesman's construction?

2 votes
3 answers
84 views

Rotated surface code vs unrotated surface code - Boundary stabilizers

2 votes
3 answers
65 views

Does the preparation of magic states need magic gates?

1 vote
1 answer
100 views

What is the formula for the matrix representation of a general controlled gate?

2 votes
1 answer
94 views

Where to find the Grover's algorithm for Qiskit 1.0.2?

3 votes
1 answer
73 views

Are concurrence $C$ and purity of reduced state $p$ related by $C^2\le 4p(1-p)$?

1 vote
2 answers
69 views

What's the best way to approximate a unitary $N\times N$ gate by a quantum circuit?

0 votes
2 answers
87 views

An Introduction to Quantum Computing - Exercise 6.4.1

2 votes
2 answers
67 views

Are all extremal points of the feasible set of an arbitrary affine equation pure states?

4 votes
1 answer
65 views

Bounds on local expectation values for two states close in trace distance

3 votes
1 answer
82 views

Can I obtain the pure state corresponding to a density matrix from its main diagonal?

0 votes
1 answer
95 views

Hello world program in Qiskit 1.0 [closed]


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