Questions tagged [error-mitigation]
For questions about QEM (Quantum Error Mitigation) which is different from Quantum Error Correction in that no extra qubits are used.
65
questions
0
votes
0
answers
22
views
Uncorrectable error due to error on ancilla qubit
Consider a controlled-NOT (CX) gate between the two qubits, implemented with an interaction of the form
$
\widehat{H}_{\mathrm{CX}}=V\left[\left(\frac{\hat{I}_1+\widehat{Z}_1}{2}\right) \otimes \hat{I}...
- 197
0
votes
1
answer
19
views
Where have the error mitigation utilities moved to in Qiskit?
Now that Qiskit Ignis has been deprecated where have the error mitigation utilities been moved to? I am unable to find that by doing a quick google search.
- 169
0
votes
0
answers
18
views
Lindblad under time rescaling: Zero noise extrapolation
This question is related to an earlier post Zero noise extrapolation for error mitigation: Meaning of rescaled density matrix, specifically when there is no local hamiltonian evolution
If I have the ...
4
votes
0
answers
48
views
Probabilistic error cancellation: how are we sure (i) the inverse noise *mathematically* exists, (ii) its expansion contains implementable operations
I am currently learning the basics of probabilistic error cancellation.
The idea, in summary, is the following:
We want to implement a quantum circuit having a noiseless (unitary) implementation $\...
- 1,142
1
vote
0
answers
53
views
Zero noise extrapolation for error mitigation: Meaning of rescaled density matrix, specifically when there is no local hamiltonian evolution
I have a few questions regarding dynamics rescaling for zero noise extrapolation. In the paper Error mitigation for short-depth quantum circuits, in equation (30), they write
We redefine $T \...
2
votes
1
answer
40
views
Bounds on success probability of an algorithm under depolarizing noise
The problem I have is that, I have a quantum circuit performing a certain task (e.g. Shor's algorithm) and the circuit is subject to depolarizing noise, Pauli errors, after each gate. And I want to ...
- 53
0
votes
0
answers
16
views
how does one get native 2-body measurements?
How are Majorana-based architectures able to possess native 2-body measurement operations? Could anyone provide an appropriate reference explaining that?
Are those native measurement operations ...
- 153
3
votes
2
answers
111
views
How to transform a qiskit quantum circuit to a braket circuit?
I have a quantum circuit in qiskit. Now I want to know is there any way that I can transform it to a braket circuit in AWS?
I want to use error mitigation in AWS. I have the circuit in qiskit. But as ...
1
vote
1
answer
80
views
Measurement of readout errors for error mitigation algorithms
I am using an error mitigation algorithm that uses the readout errors p(0|1) and p(1|0) to correct the errors due to noise in my original circuit. I am trying to measure the readout errors in the same ...
- 169
0
votes
0
answers
89
views
Qiskit, possible to manipulate mid-circuit measurement outcomes?
I'm currently coding up an error correction gadget using qiskit.
The one I'm doing now is 7-qubit Steane code with Steane's error correction gadget, in which the ancilla qubits are measured and then ...
- 53
4
votes
0
answers
40
views
How is randomized compiling actually helpful: experimentally, a gate is not "perfect" followed by some noise acting "after"
I am currently learning randomized compiling with this paper which seems to be the "main" reference on this topic (at least many papers refer to this one).
However, I do not understand how ...
- 1,142
1
vote
2
answers
142
views
What do the 'resilience_level's in qiskit-runtime's primitives mean?
The qiskit-runtime primitives programs 'estimator' and 'sampler' for accessing the IBM Q hardware have the option of error mitigation by setting the 'resilience_level'.
Here an overview of the meaning ...
- 115
2
votes
0
answers
145
views
How is Pauli twirling applied to a noisy gate in practice?
My understanding of Pauli Twirling mainly comes from this paper. Please, correct me if I am wrong in any part of my explanation.
General idea of Pauli twirling
The idea of Pauli Twirling is the ...
- 1,142
1
vote
0
answers
51
views
Time Complexity (Big O Notation)
What is the time complexity of the two error-mitigation methods that are implemented in qiskit.ignis.
1- pseudo inverse.
2- least squares.
2
votes
1
answer
37
views
Which error channel definitions should I use if I want to compare the performance of a QEC protocol for depolarizing errors vs dephasing errors?
Let's say you want to investigate if a quantum error correction or error mitigation protocol performs better under dephasing errors compared to depolarizing errors, or if a quantum algorithm is more ...
- 566
0
votes
0
answers
31
views
Does anybody know what a low-degree Markov field is?
In the paper Fast Estimation of Sparse Quantum Noise I saw the following description:
quantum devices approaching the fault-tolerant regime will have very
few significant errors (and therefore are ...
- 457
3
votes
0
answers
93
views
Are there any systematic tools for estimating expected error rate?
Like we all probably know, today’s NISQ computers are, as their name implies - very noisy. Hence, if we desire to obtain valuable results then we should come up with circuit designs that minimizes the ...
- 1,624
2
votes
1
answer
316
views
Best tutorial about the variational quantum eigensolver (VQE)
I want to find a tutorial on VQE with a good valance between the theoretical background of the method, and it's working implementation on QPU. Covering advanced topics such as quantum error ...
- 245
4
votes
1
answer
166
views
Is there a tutorial for error mitigation in qiskit that does not use the deprecated ignis?
Working through the qiskit text I have come accross measurement error mitigation a few times (Measurement Error Mitigation, Lab 3: Quantum Measurment,...]. In the online textbook the coding indicates ...
- 452
1
vote
2
answers
82
views
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.
...
- 95
8
votes
3
answers
849
views
What is the difference between Error Mitigation (EM) and Quantum Error Correction (QEC)?
From what I understood, EM is mostly post-processing and does not affect quantum circuit complexity whereas QEC has overheads and integrates as part of a quantum circuit. Is this correct?
Also, which ...
- 2,172
2
votes
1
answer
83
views
Options for more complex error models on stim?
We're trying to simulate whether some initialization strings are preferable to others. For example, would initializing all qubits to $|0\rangle$ lead to a lower error rate?
Is it possible to further ...
- 23
1
vote
1
answer
252
views
What is the concrete difference between qiskit thermal_relaxation_error and phase_amplitude_damping_error?
What is the concrete difference between those two error models in qiskit.providers.aer.noise?
For phase_amplitude_damping_error ...
- 115
2
votes
1
answer
152
views
Readout Error in Qiskit: What is a reasonable model?
The Readout Error in Qiskit is described here: https://qiskit.org/documentation/stubs/qiskit.providers.aer.noise.ReadoutError.html
Although it is easy to obtain such an error for 1-qubit for IBMs ...
- 565
2
votes
1
answer
78
views
Implementing Readout Error in my circuit seems to have no effect whatsoever
I am trying to perform a simulation using Qasm in order to see how the readout error actually affects my circuit. The circuit I am implementing is a trivial one, the three qubit one that implements ...
- 565
3
votes
1
answer
75
views
How to set the meas_level and optimization_level in Quantum Azure IonQ provider?
I am performing a benchmark process using the Azure Quantum IonQ provider. I use Qiskit in the Azure platform, and I was trying to see how to control the transpiling and compiling process. It seems ...
- 284
2
votes
1
answer
54
views
Can ancilla-based parity measurements be used to detect errors in NISQ algorithms?
Measuring stabilizer eigenvalues is a fundamental part of quantum error correction. However, I was wondering if the idea of measuring a stabilizer using an ancilla could be useful in other contexts as ...
- 1,180
2
votes
2
answers
147
views
Surface Code Eigenstates as Circles
I learned that logical $|0\rangle$ of surface code, is an eigenstate, where all stabilizers are +1 value, and since the z-stabilizer is enforcing an even amount of edged in each node, and the x-stab ...
- 1,124
0
votes
0
answers
30
views
Code Length of most Naive Repetition Code
What is the formula or answer to the following coding: I would like to get logical qubit with logical error rate of $P_L=1E-10$ or $P_L=1E-19$ for Shor's algorithm, but I would like to know how many ...
- 1,124
3
votes
0
answers
387
views
Add noise_model when using 'ibmq_qasm_simulator' backend and provider.runtime.run() function
I am trying to test some qiskit code that employs readout-error mitigation using the ibmq_qasm_simulator backend and Qiskit Runtime. I am getting the backend as ...
- 31
2
votes
1
answer
33
views
Qubit State (theta,phi) Dependence on the Readout Error
Do the readout errors on the publicly available IBM quantum computers have any dependency on the state being measured? That is, if we are measuring a qubit in the state
$\cos({\theta/2}) |0> + e^{i\...
- 55
2
votes
3
answers
226
views
Surface Code - Convert Control Error to Clifford Error
I am simulating surface code, in order to find the logical error as a function of control error in my circuit.
Each of my data qubits is multiplied in control error = a unitary matrix $U$ which is ...
- 1,124
2
votes
2
answers
270
views
How to calculate the number of qubits in surface code, for given physical error rate
I am working on improvement of physical qubit error probability.
I would like to know: how to calculate the size I need for surface code, given that I need that the logical error probability will be ...
- 1,124
4
votes
3
answers
374
views
Why does making a quantum circuit more noise resilient make it easier to simulate classically?
I was reading Quantum Computing in the NISQ era and beyond (John Preskill, 2018) but I didn't get this point on pages 9-10:
There is a substantial opportunity for experimentalists and theorists, ...
- 143
1
vote
1
answer
98
views
Correcting Coherent errors with Surface Codes
Following this article: Correcting coherent errors with surface codes
I wonder about the modeling of coherent error and its effect on syndrome after measurement.
They say that applying U on the ...
- 1,124
5
votes
0
answers
98
views
Which improvements can we expect in Quantum Error Correction?
According to this article:
The surface code is currently the most widely pursued quantum error correction scheme
(Emphasis mine). It is also said:
However, there are drawbacks to the surface code, ...
- 4,628
4
votes
1
answer
158
views
How can I add readout error in constructing a quantum noise model?
I'm trying to construct a quantum noise model with readout error only: qiskit.providers.aer.noise.NoiseModel.add_readout_error. However, when I try to specify the ...
- 2,348
4
votes
1
answer
120
views
Nyquist–Shannon sampling theorem for Quantum Evolution
In classical digital signal processing one can try to identify the dynamics of a system by sampling its evolution from an initial time $t_0$ to a final time $t_1$. Sampling $N$ times results in a ...
- 565
2
votes
1
answer
163
views
Confusion about Mitiq folding for zero noise extrapolation
I'm reading the mitiq zero noise extrapolation documentation and I just can't make sense of how the scale_factor for folding work.
"The minimum scale factor is one (which corresponds to folding ...
- 31
3
votes
1
answer
171
views
How to use Clifford Data Regression for the MaxCut Problem
i read about Clifford Data Regression in https://arxiv.org/pdf/2005.10189.pdf.
If I have understood this correctly, then one receives the mitigated expected value of an observable from CDR.
For the ...
- 53
1
vote
2
answers
56
views
Is it possible to use the mitigation process on a teleportation circuit?
Is it possible to use the mitigation process on a teleportation circuit? Sorry, i'm still starting, if someone can get me out of this doubt, I would appreciate it. The circuit I'm trying to make this ...
- 79
2
votes
1
answer
225
views
Is there a faster way to do real-time error mitigation in qiskit?
I'm working on the readout error mitigation on a set of results obtained from different quantum circuits. The method I want to apply is to generate the confusion matrix for each quantum circuit (as ...
- 2,348
1
vote
0
answers
61
views
How to measure the error rate (or fidelity) of a particular gate (such a H, T) by Qiskit
We know the calibration data of IBM's quantum devices can be retrieved through the randomized benchmarking method, which is included in Qiskit. However, the calibaration data about gates just gives ...
- 71
2
votes
1
answer
102
views
About qiskit's error mitigation
In qiskit, the error correction using least squares is apparently in qiskit-ignis/qiskit/ignis/mitigation/measurement/filters.py, source code from github and reads:
...
- 447
0
votes
1
answer
123
views
Manual measurement error mitigation returning a negative number of counts
I have a simple 2 qubit circuit which I am trying to protect from errors using the measurement error mitigation technique laid out here:
https://qiskit.org/textbook/ch-quantum-hardware/measurement-...
- 343
1
vote
1
answer
401
views
Guide for Qiskit's Measurement Error Mitigation?
I'm reading about error correction mainly in the Qiskit Measurement error mitigation chapter contains what it seems and easy way to "clean up" the noise obtained in the IBM (or NISQ) devices....
- 447
8
votes
2
answers
455
views
Apply readout error mitigation to mid-circuit measurement
I'm trying to construct a quantum circuit with 3 mid-circuit measurements, here's an example:
...
- 2,348
2
votes
0
answers
45
views
Crosstalk error of simultaneous cnots
We can use simultaneous randomized benchmarking (SRB) to quantify the crosstalk impact of simultaneous CNOTs. The crosstalk error is caused by many reasons, for example, the always-on ZZ interaction, ...
- 1,303
4
votes
1
answer
166
views
Filtering a set of results obtained from job manager
I've already generated a filter for readout error mitigation:
...
- 2,348
1
vote
1
answer
58
views
Can I only use a 'subset' of calibration matrix to reduce measurement errors?
Suppose I have the following calibration matrix generated using 4 qubits:
...
- 2,348