All Questions
Tagged with quantum-gate noise
20 questions
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Can we somehow relate quantum volume with the total number of gates present in a circuit which the machine can succesfully run without large errors
Let's say I have a circuit which contains x number of gates and a machine with quantum volume y, Can I relate x and y somehow to determine if the circuit can be succesfully run on the machine without ...
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Is this quantum circuit design more prone to noise?
I am designing a quantum circuit which uses one qubit as the control of many $\text{CSWAP}$ operations. And then, this qubit will be measured.
Will the result be more prone to noise since all the ...
- 231
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120
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What are efficient methods for measuring gate noise?
In this question I'm concerned with getting detailed spectral information about analog noise in quantum gates.
Assume we have imperfect control over transitions between $\vert 0\rangle$ and $\vert 1\...
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341
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Is there a way to implement a noisy CNOT gate using CUGate in Qiskit
Wondering if there's a way to implement the noisy version of CNOT (or CX) gate via CUGate using qiskit library for a given fidelity p?
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Exploiting virtual-$Z_{\theta}$ corrections in QEC
The work done by IBM Researchers to perform virtual-$Z_{\theta}$ gates allowed them to:
achieving zero-time relative phase shifts;
correcting $Z_{\phi}$ errors occurring when applying some gates -- e....
- 2,058
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Propagation rules for the cross-resonance gate of IBM ($R_{zx}$)
The $R_{zx}$ is the fundamental two-qubit gate supported by IBM processors. I'd like to see how Pauli operators propagate over such a gate.
Other well-known cases are shown in the picture below.
- 2,058
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2
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408
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What is more important, minimizing the number of gates, or the number of qubits?
I am new to the quantum world, and I have 2 circuits that measure cosine similarity between 2 binary vectors. One uses a swap test, the other uses something called a hyper-state generation procedure.
...
- 105
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161
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Is it possible to find a cNOT implementation that preserves a biased $X$ noise
I am interested in qubits which are biased in noise. For my purpose I assume that I have only bit-flip (i.e. Pauli $X$) noise in my algorithm.
In the presence of such noise, quantum gates can convert ...
- 1,952
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105
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Qubit Resource Estimates for 2D Ising Model
I recently came across this paper where the 1d Transverse Field Ising Model (TFIM) with $n$ spins was simulated on a quantum computer. The estimated resources were $n^2$ for the number of gates and ...
- 121
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What makes dynamical decoupling a good method since the fidelity after using it can only reach 0.85 or so?
From this paper, I see that the fidelity of single qubit gate after using dynamical decoupling only reach around 0.85 while I normally saw experiment papers state their fidelity can reach around 0.99 ...
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How does an $\sqrt{X}$ error propagates through an $T$ gate?
I wonder whether there is a compact way of describing a noise $\sqrt{X}$ propagating through a $T$ gate. Possibly in terms of Pauli and/or Clifford operators.
- 2,058
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Error Model on id gate, is not giving any error
I am trying to play with NoiseModel of qiskit, and I noticed that error on id gate is not giving any error results, while error ...
- 1,502
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227
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Iterative Phase Estimation with noise vs standard Quantum Phase Estimation with noise
I am doing Qiskit Lab 4 about Iterative Phase Estimation. I created a circuit implementing IPE for theta = 1/3 (phase of 2pi/3). Here's the circuit:
It seems to do okay if I run it without noise in a ...
3
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239
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What are the possible gates that I can use to vary input states before CNOT?
We know that the noise of the $\text{CNOT}$ gate varies depending on the input state before it.
What are the gates that I can put in the place of the 4 identity gates above to change the input state ...
- 79
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What do the "gate errors rates" mean physically for IBM's quantum computers?
I wish to simulate the gate errors from IBM's various quantum computers. However I am not sure what the gate error rate physically means. An error rate of say 0.01 for a particular means one in every ...
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There seems to be a bias against states with more 1s, in IBM's calibration matrix generator: What are the consequences and possible solutions?
Qiskit's function CompleteMeasFitter builds a calibration matrix in this way (2 qubit case):
Everything is initialized in the state $|00\rangle$, which is the ...
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210
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How does noise affect the implementation of quantum gates?
I am trying to think about quantum noise visually here. If, for example, one wants to implement an X-gate to perform a 180-degree rotation around the Bloch Sphere. In a perfect world, the X-gate will ...
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Why should we use density matrices to simulate quantum systems with noise?
Why we should use density matrices to simulate quantum systems with noise?
I found that the any QEC circuit is included by some quantum gates just like normal cases, which means the state vector can ...
- 467
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165
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Why are two qubits gates more noisy?
I would like to understand why two qubit gates are generally more noisy.
If I am interested in single qubit gates, I can have an effective modelling as a master equation:
$$\dot{\rho}=\frac{1}{i \...
- 1,952
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144
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How do I know in which state the qubit is in each step of the circuit for the simulator in qiskit?
I would like to know how to know in which state a qubit is (I am talking about single-qubit errors), because in order to apply a non unitary gate in the simulator I have to renormalize the state or ...
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