Newest Questions
12,710 questions
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What is the circuit that simulates this unitary [closed]
What is the circuit that simulates the following unitary matrix?
$$
P = \begin{bmatrix}
0 & 1 & 0 & 0 & 0 & 0 & 0 & 0 \\
0 & 0 & 1 & 0 & 0 & 0 & 0 ...
- 59
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Proof of Theorem 3 in Quantum Singular Value Transformation by Gilyen et al
I was recently going over the first proof in Gilyen et alia."Quantum singular value transformation and beyond:
exponential improvements for quantum matrix arithmetics" https://arxiv.org/abs/...
- 25
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40
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How does Qiskit's inverse `prepare_state` operation work?
I'm trying to understand Qiskit's inverse and prepare_state operations together. The simple example below shows a circuit where ...
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0
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29
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Automated methodology / tool to find logical operators for QEC codes
Is there a standard tool or automated methodology to find logical operators for arbitrary stabilizer QEC codes (or specific families of codes?). I am aware that one could work through the math and ...
- 21
4
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2
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557
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Can multiple quantum programs run simultaneously on a real quantum computer?
Quantum cloud platforms often receive numerous job submissions from users around the world. If multiple jobs request execution on the same real quantum device, is it possible for these quantum ...
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2
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376
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How does one implement Hadamard gate in Pauli-based computation?
Pauli-based computation supposedly gives the full Clifford group.
For instance, the CNOT can be implemented using joint ZZ measurement and joint XX measurement and using an additional ancilla qubit.
...
- 81
3
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79
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Can QEC Handle Continuous Errors Like Rotation and Dephasing?
"I've recently started learning about Quantum Error Correction (QEC). I notice that many papers focus on discrete errors like bit-flips and phase-flips (Pauli errors), and I understand that ...
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103
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Circuit for the boundary of the hex grid surface code
I noticed that the "3-coupler" surface code example circuit in Crumble differs from the one in the paper Relaxing Hardware Requirements for Surface Code Circuits using Time-dynamics, on the ...
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Qiskit Quantum Composer Swap-Gate doesn't seem to be working properly
I have been experimenting with the swap-gate in Qiskit's Quantum-Composer and I'am confused:
Initialized two qubits with 0, a not-gate on q[0] results in the state 01:
I expect a subsequent swap-gate ...
2
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1
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51
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Complexity of deciding whether a subcomponent of a pure state is unentangled
Suppose I have an $n$-qubit pure state $|\psi\rangle$ that I can prepare using a unitary $U$ s.t. $U|0\rangle = |\psi\rangle$. I would like to determine whether the first qubit in the system is ...
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Using modular multiplication remainder value to factorize
There exist modular multiplication circuits to implement from $|xy>$ to $|x>|xy mod N>$ like in this article, I guess the resulting state from this unitary in the second register is the ...
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2
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2
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Do logical operations map stabilizer group to itself?
Say we have a $n$-qubit stabilizer code $Q$ with stabilizer group $S$. If unitary $\bar{K}$ is a logical operation that preserves the codespace, what conclusion can we draw for $\bar{K}$ and $S$?
If $\...
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Why does manually applying Hadamard + RZ gate give different results than Qiskit ZFeatureMap?
I'm trying to understand how different quantum feature maps encode data. As part of this, I'm attempting to manually construct the same statevector that Qiskit's ZFeatureMap produces, using my own ...
- 13
3
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2
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296
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On Pauli matrices being a basis for unitary transformations
I am confused about the Pauli matrices. I am trying to decipher a statement like this:
"[...]these three operators form a complete basis for the set of all unitary transformations on a single ...
- 167
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3
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201
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How can we build a unitary that implements the negative identity operator
I just want to know how we can build a unitary (using arbitrary 1 or 2-local universal quantum gates) that implements the operator:
$- \mathbb{I}$.
So $\sum_x \alpha_x |x\rangle \mapsto \sum_x -\...
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