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Quantum Computing

Notable Question

 Notable Question
Question with 2,500 views. This badge can be awarded multiple times.
Awarded 227 times.
Show that a $CZ$ gate can be implemented using a $CNOT$ gate and Hadamard gates
Awarded May 28 at 19:49
How to initialize classical register in Qiskit?
Awarded May 25 at 7:17
Is VQE a class of algorithms or a specific algorithm?
Awarded May 24 at 11:19
How does the CX gate work?
Awarded May 20 at 23:12
How to prove that antipodal points on the Bloch sphere are orthogonal?
Awarded May 18 at 19:41
How do I apply the Hadamard gate to one qubit in a two-qubit pure state?
Awarded May 13 at 15:35
IBMQ.load_account from stored ACCOUNT is failing on Qiskit 0.9.0
Awarded May 10 at 20:40
Error: cannot import name 'BaseBackend' from 'qiskit.providers'
Awarded May 6 at 0:10
Updating qiskit doesn't update qiskit version using jupyter notebook/terminal
Awarded Apr 29 at 15:40
Why do quantum gates have to be unitary?
Awarded Apr 29 at 4:31
What does it mean to express a gate in Dirac notation?
Awarded Apr 27 at 9:05
Can a quantum computer break quantum cryptography?
Awarded Apr 14 at 2:12
Does anyone know the list of all known universal sets of quantum gates?
Awarded Apr 8 at 20:35
Measure a state in Hadamard basis [closed]
Awarded Apr 6 at 3:56
Big Endian vs. Little Endian in Qiskit
Awarded Apr 4 at 14:51
Quantum Computing Qiskit - How to read data from classical registers
Awarded Apr 4 at 5:36
Quantum Supremacy: Some questions on cross-entropy benchmarking
Awarded Mar 31 at 10:52
What is the relation between these two forms of a single-qubit unitary operation?
Awarded Mar 21 at 11:16
How to add several parameters in qiskit circuit?
Awarded Mar 19 at 6:41
How can I decompose a matrix in terms of Pauli matrices?
Awarded Mar 17 at 4:34
What is the difference between QAOA and Quantum Annealing?
Awarded Mar 4 at 21:34
If quantum gates are reversible how can they possibly perform irreversible classical AND and OR operations?
Awarded Feb 27 at 4:21
What's the physical significance of |0⟩ and |1⟩?
Awarded Feb 23 at 4:30
Proof of no-cloning
Awarded Feb 19 at 20:56
How to find the operator sum representation of the depolarizing channel?
Awarded Feb 12 at 16:49
How do 2 Hadamard gates act on a single qubit?
Awarded Feb 8 at 20:11
What is a Haar random quantum state?
Awarded Feb 8 at 4:10
Why are non-Clifford gates more complex than Clifford gates?
Awarded Feb 3 at 19:17
How accurate is this figure by TIME magazine?
Awarded Feb 3 at 17:35
How to fix an error : " QiskitBackendNotFoundError: 'No backend matches the criteria' "
Awarded Feb 3 at 9:16
Is quantum computing mature enough for a computer scientist with no physics background?
Awarded Jan 28 at 12:35
What is a stabilizer state?
Awarded Jan 27 at 13:12
What is the difference between "code space", "code word" and "stabilizer code"?
Awarded Jan 27 at 10:03
How to visualize Hadamard gate as $X$-$Z$-$X$ decomposition?
Awarded Jan 26 at 18:36
What is the "Stinespring Dilation"?
Awarded Jan 19 at 13:17
How to convert QUBO problem to Ising Hamiltonian?
Awarded Jan 17 at 14:26
import error :No module named 'qiskit_aqua'
Awarded Jan 9 at 5:03
What are the pros/cons of Trapped Ion Qubits, Superconducting Qubits and Si Spin Qubits?
Awarded Jan 2 at 21:08
How to approximate $Rx$, $Ry$ and $Rz$ gates?
Awarded Dec 27, 2022 at 12:25
How are the Pauli $X$ and $Z$ matrices expressed in bra-ket notation? [duplicate]
Awarded Dec 23, 2022 at 4:55
How to transform e.g., a 4 by 4 unitary matrix into a quantum circuit
Awarded Dec 12, 2022 at 21:11
How do I calculate the von Neumann entropy of a pure one-qubit density matrix?
Awarded Dec 10, 2022 at 14:55
What is a "maximally mixed state"?
Awarded Dec 9, 2022 at 4:35
How is a quantum computer programmed?
Awarded Dec 8, 2022 at 0:07
In Grover's Algorithm, why does the optimal number of iterations involve a floor?
Awarded Dec 6, 2022 at 15:27
Calculating the expectation value of a unitary operator on a quantum computer
Awarded Dec 4, 2022 at 15:27
How does evolving a two-qubit state through a CNOT gate entangle them?
Awarded Dec 4, 2022 at 1:11
Does control and target matter in the CZ (Controlled-Z) Gate? [duplicate]
Awarded Dec 3, 2022 at 16:27
What does "bipartite" mean?
Awarded Nov 27, 2022 at 0:09
Understanding the oracle in Deutsch's algorithm
Awarded Nov 19, 2022 at 2:01
Loading Qiskit account in the Jupyter notebook gives RequestsApiError error
Awarded Nov 18, 2022 at 14:25
Phase-Shift Gate in Qiskit
Awarded Nov 10, 2022 at 22:11
Is Qiskit more popular than cirq? Why?
Awarded Oct 24, 2022 at 23:27
How is CNOT gate physically implemented in IBM Q?
Awarded Oct 21, 2022 at 13:55
Why do computer scientists care about the phase of qubits?
Awarded Oct 18, 2022 at 15:50
How to implement a Fredkin gate using Toffoli and CNOTs?
Awarded Oct 18, 2022 at 14:22
How to show a density matrix is in a pure/mixed state?
Awarded Oct 16, 2022 at 17:11
Twirling Quantum Channels: Pauli and Clifford Twirling
Awarded Oct 15, 2022 at 13:12
What do we mean by parity of qubits?
Awarded Oct 10, 2022 at 7:09
Is qsphere an actual term representing 5 qubits?
Awarded Oct 10, 2022 at 3:04
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